I like MSP430 a lot but the tooling leaves a bit to be desired. Maybe that's been improved upon recently by TI but a few years back you were left with few choices other than installing some kind of IDE on Windows.
TI distributes a pre-compiled version of GCC [0] for the MSP430 along with a command line MSP-flasher [1] utility for flashing code to the device. It all works really well on Linux. I haven't had to touch any of their windows tools. It can be slightly confusing getting started because there are 101 different ways to develop and compilers you could use so you have to wade though examples that may not be applicable to your chosen development environment. Once you get past that it isn't hard. I really like the tutorial series on simplyembeded [2] they to a great job of covering the MSP430 basics.
