Dan Williams - This site has expired......I believe there is a mirror of it somewhere which I will post when I find it.
Inferno Labs- A nice site with info on pyrotechnics.
Wouter Vissers Practical Pyrotechnics - A great site with lots of hands on info also is in English or Dutch!
Pyropage - A site with little hands on info but the owner Tom Dimmock is an authority on a rare and difficult firework known as the Girandola!
Pyrouniverse - A great site with lots of info on putting on a display with consumer fireworks. Also a good page on ignition but none on actually building fireworks.
Short Fuse Pyrotechnics - A nice site with some Tutorials and photos.
Pretty Green Flames - A nice site with Pyro info.
Japan Fireworks - A nice site about Japanese fireworks and a lot of info.
Alany's Pyro Site - A great site with some tutorials and good fireworks.
Bielecki - A nice pyro site with info and some pictures.
Links Database - A large database of pyrotechnic, rocketry, and chemistry links. In Dutch...
Rocketry
James Yawn's Recrystalized Rocketry - A great Rocketry site with lots of info and photos!
Nakka-Rocketry - A good Rocketry Site with lots of info and photos!
TrailerTrashAerospace - A group of HP rocketeers in the desert "doin wat they can wit wat they got!" A good site, lots of nice photos and a few tutorials.
The Amateur Rocketry Links Library - The best collection of Rocketry links on the web!!
JCRocket - Nice site with photos and stories.
Rocket Article - Just an article I found with lots of info on scratch building rockets.
Rocket ArticleII - An excellent article on all kinds of rockets, seems to be old.
Liquid Rocket Article - A nice article on Liquid Articles.
Inertlam - Nice website on building a Hybrid rocket from PVC parts.
FAA Waiver Form - This is the form you would fill out to get your launch area waivered so you can fly rockets to heighths over 1000ft(the limit for civilian rockets) legally. You'll need to contact your local FAA officer and provide this form plus some red tape to get waivered.
Pyroteknix - Easy PVC rocket motors.
Suppliers
United Nuclear - A great supplier and is personally wher I get nearly all of my supplies from! Although the prices are quite high.....
Discount Pyro - I've never bought from here but have heard many good things, plus the prices are great! Requires ID however to order...
Cannon Fuse - The best site to buy fuse from and also sells some tubes and shells!
Skylighter - A great site with informative newsletters and also a respectable supplier with fairly cheap prices! However it requires ID to order....
Forums
APC Forum - In my opinion the Best Pyrotechnic, Rocketry, and Chemistry forum on the web!!
UK Rocketry Forum - A nice forum about Rocketry as well as Pyrotechnics.