Doujinshi Sites:

General: Mind Education
Trowa x Quatre: txq doujinshi, Candy Factory, Subtle Hints

Where To Buy:

Ebay GW Doujinshi Sellers: qshineq, mobiusklein, ishiishiishi, dede0721
Auction: Ebay, Yahoo! Japan
Online Shop: Chibishop, US Anime, Doki Doki Station, Aestheticism Cybershoppe, Happy Otaku House

Link To This Site:

Link Free: http://www.oocities.org/gwjunction