Free Cortex tool chains I think are always GCC based. If you want command line only then you can get a free up to date distribution from CodeSourcery who are the GCC ARM maintainers. They do a low cost Eclipse based IDE too.
For a free IDE then you are mainly stuck with Eclipse which you can configure yourself or use the Code Red or Atollic versions. I think there are integrations with some other open source IDEs too, CodeBlocks:: maybe.