I wonder if they're doing the same (virtualized OS X, which works well but is, I believe, against Apple's EULAs) or if they use actual Macs (which would be quite burdensome)...?
Edit: confused iOS and OS X. I feel stupid.
(If so, that would be news.)
Edit: While it is possible, I wouldn't by any means call it 'Supported'.
Many people have speculated about the changes in 10.7 that made it much more like iOS, with the exact idea that one day iOS and OSX will be essentially the same thing (at least from the user perspective anyway). I certainly see them heading in this direction...
Going to be interesting times .. I suppose I have to hold onto my aging 2007 MBP another year or two and then upgrade on the next generational bump.