Housing - look on the website if they have any advice. You can try calling people at the school... usually during the interview they mention housing. You will *probably* get the email addresses of most of your classmates come May or June, and you can chat with them about finding a place to live.
Financial aid - Call or email the financial aid office for help. They're the best people to talk to, not us...
Prep for classes - Enjoy your summer. Don't buy any books. Don't study in advance. Just have fun. Seriously.