There is a good list on the Absolutewrite.com forum - although I can't find the thread right now. Also, if you look at Literary Rejections website there is a good, up to date list of agents, including their preferences on there. Oh, and twitter is a goldmine of info on agents - start following #askagent and you'll start to see the active ones there.
That's the easy bit... Now for the hard bit
Have you had your book betaed by experienced critiquers, including people who read and write your genre? Friends and family, sadly, don't count so much - they're much too nice (even when they say they're being hard.)
Have you had your query read and torn apart by experienced people - preferably those up to date with what a query letter should be? Have you read all of the queryshark blog and maybe explored Query letter hell on Absolute Write.
Have you had your synopsis checked to make sure it absolutely makes sense and does what a synopsis should do?
The sad thing is, so many of us (me included) submit before we know the ropes and before we've had the feedback we really need, and then we can't submit to those agents again. The good thing is, if you hang around here, post 30 lovely posts and get to know us, you can pop your opening 1500 words up for a critique and find out if it's hitting the mark/needs work/does any of the things agents hate.