The following internship database contains a variety of useful summer options, every one of them great for gaining experience and possibly earning money. Also, many offer the opportunity to travel to new places and ALL of them will put you ahead in the job market after graduation.
Do not be afraid to call or e-mail the contact people listed. It is their job to answer your questions! Remember, you can always talk to upperclassmen on the team and always talk to your advisor or favorite department professors. Also, don't forget to apply to more than 1 (6-10 is a good number, but 1 is better than none!)
Good luck! And remember it's always more fun than you think.