I maintain a Launchpad PPA for MSP430 development. As of the time of this writing, it contains only the mspdebug debug bridge. It is built for Lucid (10.04 LTS) and Maverick (10.10). You can install it on your system by running the following command:
sudo add-apt-repository ppa:eblanton/msp430-dev
Once this is done, install the mspdebug package and you should be able to use it normally. I use it with an eZ430-F2013 and a TI Launchpad.
The good news about the compiler situation on recent Ubuntu is that the mspgcc4 build script works great. Download mspgcc4 from the git repository and build it according to their instructions, and you should be good to go.