If you are looking for an internship this summer About.com has a great articles on the top 10 internship sites to search on the web.  They recommend places like MonsterTrak, WetFeet, Idealist.org and other popular sites.

I would also recommend you talk to your career center at school, look at regional organizations who may help local companies find qualified talent, talk with professors, and of course network at job fairs.  The internet is a great place to find information about companies and learn about job openings but don’t forget the best way to find a job is through professional networking.