Macfixit has published confirmation that the MacBook Air will be the first Mac to have the ability to boot wirelessly.
During Apple's demonstration of the MacBook Air at Macworld 2008 they dubbed a new feature called "Remote Disc", this allows for discs to be accessed in another optical drive over the network from the MacBook Air. Included with this functionality is the ability for the MacBook Air to wirelessly boot off of a Remote Disc shared drive.
MacRumors adds that Mac OS X 10.5.2 is likely to add wireless booting to all Macs according to their sources.