I recently purchased a white apple keyboard they produced from 2003-07. Apart from it being a very good keyboard it also works out of the box with Ubuntu 12.04. There is just one small detail driving me crazy, that is by default the order of the Ctrl/Super/Alt keys. Apple uses a different order for the Super (Command in the Mac world) key and the Alt key.
Here I found a blog entry by Chris Miller that does the trick: http://www.chrisamiller.com/blog/2012/05/11/remapping-your-macbooks-keyboard-in-ubuntu-12-04/