MacRumors.com

An Apple Job listing (noted on Engadget) reveals that Apple is indeed working on multi-touch Mac hardware.

They are looking for a reliability engineer supporting Multi-touch panel development with Mac and iPod hardware groups. The job itself seems to involve high level quality assurance testing, but the involvement of the Mac hardware group seems to confirm that Apple is working to incorporate multi-touch technologies into future Macs.

This progression has been widely expected since the iPhone was first released, but this is the first (possible) indication from Apple.

9to5mac had previously suggested that the Apple sub-notebook might incorporate some of these features, but no further details have become available, so the timeframe for this integration remains speculative.