Planet Tony Hawk - Information, FAQ, level guides, move and transfer lists, codes, glitches, downloads, and forum. - http://planettonyhawk.gamespy.com/
OnlineSkaters.net - Community site for the Underground series. Forum, screen shots, tournaments, and downloads. - http://www.onlineskaters.net/
Tony Hawk Forums - Discussions on multiple games in the series as well as related topics. - http://thpsforums.com/
The Skate Park Emporium - Downloads, fora, links, and ratings regarding skate parks. - http://2win.ca/spe
Jed's THPS Videos - Video clips [avi] of combos in THPS 1 and 2. Also includes message board. - http://www.sportplanet.com/thps/jedsvideos/