Go to QueryTracker! The link is on the sidebar. It has a searchable database for agents, and each agent's page links you to all the other standard resources on that agent: google, yahoo, agentquery, preditors and editors, etc. Also, other users can enter comments, so you can see what other people are saying about the agent.
And, best of all, it does what I have been doing with my own home-made chart: it keeps track of what agents you've queried, when, and what their responses are. It can also save your query for each agent online (in case of computer failure--it's not lost!), and produce envelopes and letterhead for you (you have to choose and mail the queries to the agents yourself, so it's not like one of those query blaster scams).
And it's free.....(the guy who started it three months ago, in Montana, does need donations, though, and has some cool services available to "premium" members--at $25/year. Pretty cheap except for those of us who are broke. That's a problem, for sure--so many people searching for agents are broke writers.)