We already have Bluetooth that operates separately from Wi-Fi. Both wireless functions are common on today's laptops but they run off separate chips and serve separate tasks. Bluetooth is relatively low bandwidth and relatively short distance but it is designed to be easy to use since devices are automatically discovered and then made available for use. Bluetooth is extremely common on consumer devices like cellular phones and it is excellent for downloading ring tones but less adequate for transferring videos (due to the size of the data involved).
Wi-Fi, on the other hand, was designed for networking and thus offers greater bandwidth, greater ranges, improved security and, unfortunately, greater complexity. The idea of tacking Bluetooth over a Wi-Fi signal would be to try to combine the easy of use from Bluetooth with the greater bandwidth and greater range of Wi-Fi. The first Bluetooth over Wi-Fi devices may appear as early as the middle of 2009. The goal, from a production perspective, would to have a single chip to control both functions.
So where does this leave Bluetooth UWB (Ultra-WideBand) that was announced in 2006? Well, apparently, this doesn't change anything as it will still proceed "when that technology is ready".