Resources / Links
Here are some Yu-Gi-Oh! resources worth checking out:
City of Gamers: Excellent online forums for Yu-Gi-Oh and other games.
Trade Cards Online: Online resource to trade cards from nearly every TCG/CCG out
there.
Official Yu-Gi-Oh Site
YVD: Online dueling software.
Play other CCGs/TCGs besides Yu-Gi-Oh? Check out CCGDB.com to get card details on other games. (soon to be part of the toolkit)