These links are to sites I found that look legitimate. As always when trying to find an agent, you will need to do some research yourself. I haven't personally worked with any of the companies listed below.
The Association of Author's Representatives
Writers Free Reference Literary Agents (features International agencies also)
The Ethan Ellenberg Literary Agency
I will continue to update this page when I come across any other agencies that look promising.
P.S. Some of you may have noticed that I removed S.T. Literary Agency from this page. I've seen their contract. Unless you write screenplays, my advice is: Don't do it.