Does Apple's wireless keyboard work cross-platform such as in Ubuntu, Windows and *ixes? My friend bought me the mStand here and it is quite cool passive heat conductor, placing the screen to the right level and I can use it for books etc besides laptops. It requires a wireless kbd and the only such kbd I would tolerate is probably by Apple (because it is small and function at least in Mac). Now I have different laptops such as Ubuntus, Windows and Linuxes. Can I use this keyboard with them also through Bluetooth?
Sure, there's nothing keeping it from working with Windows other than the fact that it's missing some keys. I'm not sure if it's compatible with the various distros of Linux, but you can try it out and look on their associated forums.

Also, for Windows, be sure to check this out:  http://www.kudzuworld.com/blogs/Tech/20080101.EN.aspx