@desparate senior: This website has everything you need to know:
Declaring a Major. You have to declare a major by the second semester of your sophomore year.
@rijacobson: I live in a triple right now, and I personally prefer living in a triple instead of a double. I believe that having 3 people in a room provides a better conflict resolution/mediation environment when it comes to roommate scuffles. For example, roommate fights usually involve two people, the "offender" and the "victim". In my experience, the third person (who may not necessarily be involved) can serve as a really good mediator to help resolve the situation without escalating the conflict. Also, a triple usually implies you'll have more room space overall, which is always a good thing. And you'll know one more person than if you had a double, which helps as far as making friends.
@Claris: The reasons I picked Stouffer/Mayer over the Quad and Hill are:
* the rooms are definitely bigger and I wanted to live comfortably my freshman year
* in Mayer you have a private bathroom (and in Stouffer you have a bathroom shared by your section, which is less people than a hall in the Quad) and I didn't want to live in a dorm with a communal bathroom
* in Mayer you get a private kitchen with fridge, stove, and oven and in Stouffer you share a similar kitchen with your section and I really wanted to do some cooking throughout the year
* Stouffer/Mayer has a really tight-knit community. We have house events almost every day that include movie nights, coffee/tea breaks, trips to events happening in the city, and tons of sports (we're the intramural champions, after all). Because people have the kitchens, everyone is constantly baking for the rest of the house. If you run out of meals or dining dollars on your meal plan, don't worry, everyone in Stouffer will feed you.
The exterior of the Quad is beautiful and Hill is close to a lot of buildings that have freshman/engineering classes, but both dorms have small rooms, communal bathrooms, and shoddy or no communities. Hill also doesn't have AC so it's really bad in the summer/early fall months.
If you want a double as a freshman in Stouffer/Mayer, you're limited to Stouffer Hall. The only option for freshman in Mayer hall (but believe me, it is an awesome option) is a triple. See one of the earlier questions for why I prefer a triple over a double.
I think I might have just reiterated some of the things I said before, but please let me know if you have any more specific questions about Stouffer/Mayer. I'm really glad you're considering Stouffer!
@RedPhoenix, PennGrl09, & elsaphant : I think Penn's current policy doesn't fully implement "no-loans" just yet. But I believe they are working towards this goal for the next couple of years. So yes, you have a "Parent's Contribution" and a "Student Contribution", and you are supposed to find scholarships or take out loans to pay that amount. The amount Penn covers in the grant is still very generous if you are at an income level less than $90,000 though. And I finally found the article that made me think they're working towards getting rid of the Parent & Student financial contribution:
U. raises tuition but ups aid plans - News. An excerpt from the article, which was written in March 2008:
"It was the perfect opportunity to recast the initiative," Student Financial Aid director Bill Schilling said. "Any time we talk about cost and price, we always talk about financial aid since it's an integral part of the price for those students that have financial need."
A student from a family with an income of less than $90,000 will no longer pay tuition once the improvements set in. Additionally, a student from a family with an income of less than $40,000 will not be expected to pay tuition, room or board.
Despite the increase in tuition costs, University trustees said these generous financial aid offerings in the coming years will ensure that Penn is affordable.
That's what makes me think in the next couple of years (but probably not next year) they'll get rid of the parent and student contributions as well as the loans policy.
That being said, I encourage you to appeal your financial aid packages. You can definitely get some more aid if you appeal with legitimate evidence that shows you can't pay the amount they want you to pay.
@sleepingbeauty: No, you can easily opt out of a residential program after being in it for a year. You can then move to another dorm or a different residential program. And yes, you can apply to multiple residential programs. You mark these residential programs down as part of your "Top 8 housing choices". Penn then tries to match you with your top choices. But yes, you can put as many residential programs down as you want. Just don't forget that residential programs have their own application process that you'll need to go through as well.
@Motherof2girls: I talked to my nursing buddy from down the hall. She says: "The Penn Nursing program is very well-respected. We're consistently in the top 3 nursing schools in terms of receiving research grants from the NIH. The hospital areas are basically on campus. Clinicals (which you'll start sophomore year) are in groups of 8 usually, so you'll always have someone to walk with. All of your clinicals will be over by 9 PM at the latest. And in "college time", that's really early! Everyone is still out and about on campus, so it's not like you're walking down a dark alley alone.

OB (labor and delivery) clinicals are mostly off-campus due to the recent closing of multiple OB units in the area because of rising malpractice insurance. The location of the OB clinicals are about 25 minutes away by train."
@indianahoose: I know people do get away with using drugs in their room. It ultimately depends on your RA/GA and how they want to handle the situation. That being said, I agree with tickytock14 that if you take certain precautions you can get away with it. I wouldn't recommend doing it, though. My experience on the issue is limited, so I don't know what kind of punishment you would get if you were caught.
@CrystalPineapple: I talked to my friend who is currently taking BIOL 121. She says: "The class average on the midterms this semester have been 65 and 67 out of 100, respectively. The class is curved, and it is a hard curve. I think less than 15% get A's. That being said, it's like AP Bio, but there's more material covered. The lab can be challenging if you've never done one before. It's not too bad overall, though."
@elsaphant: The atmosphere at Penn is overall competitive, yes. But not the cutthroat kind of competitive that you might see in movies about elite colleges. Almost everyone who comes to Penn was at the top of their class in high school, was the president of the NHS at their school, and received awesome scores on the SAT and ACT. Therefore, for most students, it's in their nature to try to continue this success in college. Of course, this creates a competitive environment. The general population studies hard and makes good grades. But there are definitely pockets of students that party all the time and receive lackluster grades. I personally believe Wharton is a lot more competitive than the other schools, although I get the feeling Engineering is also pretty competitive. But like I said, no one is going to try to sabotage you to get ahead. Generally everyone here plays by the rules. And usually students don't ask each other what grade they received on tests and quizzes. It's a step above what you might have experienced in high school.
Sorry for the delay in answering all of your questions! Hopefully it was worth the wait.