The only wearable technology that Apple has produced is the Nike+ iPod kit. When stuck inside a sneaker (or attached to the laces), it feeds information to an app running on an iPod or iPhone regarding a jogger's speed, distance, calories burned and so on. While serious runners have questioned its accuracy, it has motivated a number of otherwise couch-bound geeks to hit the street.
As Computerworld points out, Apple has patented a large number of wearable fitness devices lately. Perhaps it's these that DeVaul will be working with, though we imagine that such a brilliant engineer will have his own ideas. In either case, we're looking forward to what comes of this new collaboration.