You should check out:
Scholastic Art and Writing Awards
Foyle Young Poets
Google - John Fox 33 writing contests for Teens (this will have a lot of different contests for you to consider entering)
Some other summer programs in addition to those suggested by @MIP750:
Duke Young Writers Workshop
Iowa Young Writers Workshop (also has online programs in fall and spring)
Bard Young Writers Workshop
University of Virginia Young Writers Workshop
Smith College Young Writers Workshop
Belin Blank Young Writers Summer Residency
Ellipses Online Young Writers Courses
Bennington Unbound Online writing courses
I would also suggest that you look at any local colleges or universities within 30-45 minutes of your house and see if they offer summer writing programs for high school students. Those are often much lower cost and allow you to commute. Google your town name and writing programs as well. For years, a local arts high school would offer a commuter writing camp around here.
You should start planning your summer now. Most programs will likely ask for a writing sample, possibly a letter of recommendation and some have deadlines that are a lot earlier than you would anticipate. Many of those summer programs offer reduced tuition and need based aid.