In particular, the Bullet vehicle seems broken, and some soft-body demos don't work.
No new features or benefits are added yet, but a few improvements are planned before Blender 2.49 release.
Please update the build systems, and add those 3 files:
extern/bullet2/src/BulletCollision/CollisionDispatch/btActivatingCollisionAlgorithm.cpp
extern/bullet2/src/BulletCollision/CollisionDispatch/btGhostObject.cpp
extern/bullet2/src/BulletCollision/CollisionShapes/btConvexPointCloudShape.cpp
I'll watch the Blender mailing list, in case this commit causes some issues.
HELP BUILD SYSTEM MAINTAINERS: Please help with updating all build systems: the newly added files need to be added. Note that the src/SoftBody has been added for future extension of real-time soft bodies.