Here are some links which I have found useful and/or indispensable.

Bands:
Kevin Dorsey Collective
Red Raville Big Band Sounds

Instrument and gear resources:
SamCo Music (Awesome repairman in upstate NY, does custom work for musicians worldwide!)
1800USA Band (Great deals on B-Stock instruments)
Musician's Friend (Gear for the working musician)
American Music Supply (More gear for the working musician)
Woodwind & Brasswind (Great deals on instruments)

Education:
JW Pepper (Great place to buy music)
Penders Music (Another great place to buy music, especially jazz!)
Kididdles.com (Music and lyrics for kids)
Dorn Publications (THE resource for saxophone music on the web!)
Jazzbooks.com (Great jazz resource here; books, play-alongs, etc.)
Kendor Music (Music for big band and combos)
West Music (Great resource for classroom music and materials)

Technology:
Apple.com
Rapidweaver (I used this app to create this website; very intuitive)
Finale Music (Professional music notation software)
Rogueamoeba.com (Music utilities for your Mac)
Hairersoft.com (Amadeus music editing software)