According to: [Register or Login to view links] it looks like it does integrate well with Visual Studio 2003 and 2005, but if you look at the bottom of the page, they say:
"To order ProDG for PlayStation®3 please contact your Sony Computer Entertainment Account Manager.
NOTICE: These products are only available to Sony Computer Entertainment's licensed developers/publishers."
This means that its not free.
If you'd like, you could try this: http://domino.research.ibm.com/comm/research_projects.nsf/pages/cellcompiler.index.html
I am not a compiler expert, but I guess that you could also create a gcc cross compiler toolchain like some of the other devs. I am a big proponent of linux, and would love to use the full capabilities of the PS3 (including RSX). I hate what $ony is doing to the supercomputer they sold us! Please help us free the PS3 devs!