According to the March issue of Nintendo Power, 11 new developers have signed on to develop GameCube games. Here is the breakdown:

Absolute Quality
Digital Concepts DC Studios Inc.
Digital Integration
Doki Denki Studio
EXAKT Entertainment, LLC
FarSight Studios
Fletcher Callen Ltd.
Gearbox Software
Semi-Precious Studios
Shaba Games
United Developers

It appears as though there is a strong chance of Half Life coming to the GameCube... More details on that in our Half-Life destined for GameCube? story!