A nice quick post on how to get the logitech media play cordless mouse working, and by working all buttons work, and its compatible with rhythmbox or whatever music player you choose really. Simply go to the following website: http://www.hidpoint.com/hidpoint/download.html
There you will be able to download a program called hidpoint which installs the necessary drivers. You will download a .bin file, and the way to get this installed in Ubuntu is by opening up terminal, cd to the directory where the bin file is located, and then type the following command:
chmod a+x nameOfBinFile.bin
Then start the installation process: sudo ./nameOfBinFile
Make sure you tell the application that have the mediaplay mouse installed with no keyboard, and then give ur comp a restart, and everything should be hunky dory! To access the configuration utility, it is under Applications -> Other -> HID something or other
Hope this helps!