READ CAMPBELL. THE END. :P
There is no known, reliable source for semis. I have maybe one or two that I nabbed through hard work and Google stalking. I suggest you do the same. (It's just not as fun if I give them to you outright.
I read some of Albert's at boot camp. It seems to be fairly excellent; one of the counselors said that it was great. We never used Marieb, and the anatomy/physio is not as involved as it could be on all three levels of testing. (Sadly. Because I'm a huge physio fan.)
They'll expect you to know about AP Chem-level chemistry. I took AP, and found it bearable. Some people didn't, and struggled with it a bit. If you're taking biochem, you should find the USABO chemistry very manageable.