on the issues
If you're trying to cut through the PR bullshit and find out what the presidential candidates actually stand for, I highly recommend OnTheIssues.org. It lists quotes and voting records on a variety of issues for each candidate, all laid out in a clear format so you can easily compare positions.
This page lists all declared presidential candidates and links to their positions. Only Democrats and Republicans so far, but in 2004 they also included third-party candidates. I assume they'll do the same next year when we get closer to the election.