The official website: Wicked The New Broadway Musical
Info at Stephen Schwartz’ official site: Wicked – a new musical
A fantastic fan site: Unexamined Life – a Wicked Fansite
The first fan site: Wicked the Musical
Lots of fan sites for this show :-): Defying Gravity
Another great fan site: Wicked, a new musical
And yet another fan site: Wicked