One main reason why people do not switch away from iTunes is that all their songs work just on iTunes. Zune and many other companies should have a converter built into their application. iTunes has a little converter that converts the files to mp3s. Hopefully this will be in the software update that is coming out on the 13th of November.
Beginning November 13, Zune® will be providing service and software updates for your device and your PC. The updates will be automatic, but you’ll need to accept the terms of service in order to receive the latest features. See the latest features >
On a side note, COD4 comes out tonight!