I used to have Spaces enabled on my old Mac system and loved it. A different virtual screen for different apps. On Mac OS X 10.8 Mountain Lion, however, I can't figure out how to enable it and get Spaces working again and it's driving me crazy. Help!

I am always listening to music on iTunes - I love, love, love it! - but since I make extensive use of Spaces, it's frustrating to have the iTunes control window always in the wrong place. is there some way I can download or otherwise make it a little controller that can be neatly tucked into the corner of ALL my Spaces?

I've become a big fan of Apple's Spaces system which lets me have a bunch of virtual screens on my laptop. This is particularly helpful when I'm playing games and (trying to) working at the same time. Thing is, I really want to have a few apps appear on all my Spaces, not just one. Is that possible?