Sax on the Web -- biggest discussion group about all things saxophone on the web
Saxophonists Anatomy -- new study just published with pictures and videos of players' vocal tracts during playing 
UNSW -- the best reference for woodwind acoustics on the internet
Saxpics -- a lot of photos of vintage saxes here
Cafe Saxophone -- UK based sax discussion forum
Choosing a Mouthpiece -- Pete Thomas has a good article here about some mouthpiece basics
Matt Otto -- Matt has a ton of great free lessons here