Preditors and Editors was created for writers and is a great watchdog for agents and publishers. You can check any agent out here at www.anotherrealm.com/prededitors.
Check out www.agentquery.com for a comprehensive list of literary agents. Know your genre and follow their submission guidelines for the best results.
Check out www.writers.net for a wonderful forum to ask other writes questions about submission guidelines and other writing related questions.