The Colle System Players Forum
A database of Koltanowski-Phoenix games (Note that most of these games were played before there was any published treatise on the topic, so the lines employed are generally sub-optimal.)
A database of Zukertort-Phoenix games (The Z-P is Rudel's suggested improvement for the Colle-Zukertort mainline. It is featured in Zuke 'Em and utilizes the same b4-lunge as the K-P.)
The Moment of Zuke, a strategy guide for both c3-Colle and b3-Colle players.
Fight the King's Indian, Grünfeld and Dutch Defenses with Zuka, a complementary system that integrates with any traditional 1.d4 repertoire (both for those who use 2.c4 and for those who use 2.Nf3).