greg2fs
I am currently looking at CamBam, it claims to be able to control the 4th axis, but I have yet to test this claim. I just have a slight issue (most probably operator fault, by default) in that I cannot get the G-code produced in CamBam to load to Mach even with M<ach set as the post processor in CamBam.
It also seems very affordable (think it's 149$) as opposed to cam's like BobcadCam, way over my entire years earnings, so I could never afford that.