Dirt Rag is probably the only bike magazine worth reading, probably because most of their articles manage to tackle interesting tangential subjects, rather than constant blather about the latest, greatest, carbon fiber widget.

Mtbr.com is a good site to get into idiotic arguments with other people who are bored at work. Seriously, there's some good info there. There's also a lot of complete BS.

TrueTemper Sports builds the tubing that I use to build your bike.

Security supplies me with parts.

J&B is another distributor I work with.

Weightweenies is a site that lists weights for various components, and is much more accurate than manufacturer's claims. Only for the seriously brain-damaged, but informative.

Sheldon Brown is THE god of bicycle tinkering. His site has something for everyone, though it's aimed mainly at home mechanics and tinkerers.

Bicycle Forest has the most excellent BikeCAD - design your own frame online! For free!

Anvil Bikeworks has tons of good info. I got my frame fixture from Don Ferris, the owner/proprietor.

Frameforum is a website for framebuilders to get in dumb arguments and sometimes also share info.

The Framebuilders email list is something I unsubscribed from long ago due to signal/noise issues. The archive has good info, though.