Apple has announced OS X 10.8 Mountain Lion, the next step in what is a clear plan to iOS-ify the Mac.
But will your current Mac take the update? The first thing to know is that you will definitely need to have OS X 10.6 Snow Leopard or later because you'll need to download it via the Mac App Store.
We're not yet sure whether it's a requirement that you have OS X 10.7 Lion, though we wouldn't be too surprised.

OS X 10.6 Snow Leopard phased out support for PowerPC processors, so once again things are Intel-only. Here's the full list of Macs and OS X 10.8 compatibility:
  • MacBook Pro - you'll need to have either a 13-inch from mid-2009 on or a 2.2/2.4GHz 15-inch or a late 2007 or newer 17-inch
  • MacBook - 13-inch 2008 in aluminum, early 2009 or later
  • MacBook Air - it needs to be ate 2008 or newer
  • Mac Mini - it needs to be early 2009 or newer
  • iMac - it needs to be mid 2007 or newer
  • Mac Pro - it needs to be early 2008 or newer
  • Xserve - early 2009
Unfortunately those Macs that won't be able to upgrade are numerous, including all the plastic model MacBooks before 2008, pre mid 2007 MacBook Pros and Mac Mini/iMac and most notably the original MacBook Air. You know, the one that came out of that famous envelope. In terms of graphics support this means anything with the ATI Radeon X1600 or an Intel GMA 950 or x3100 integrated graphics card.
Even the 2006 and 2007 versions of the Mac Pro won't be able to install OS X 10.8
Obviously all these details are based on the OS X 10.8 Developer Preview and may change for the full release. One thing's for sure - our G4 PowerBook is looking decidedly old now.
MacBook air os x 10.8