A few weeks back HTC announced they weren't bring out the much anticipated Gingerbread update for the desire. Needless to say a lot of people weren't happy to hear that news, and after countless emails and complaints, they reversed their decision. That was all just a few weeks ago, and the latest from HTC's Facebook page is that the update is already in the testing phase.
The original reason for the update seeming out of reach was because the Desire didn't have enough RAM to handle the bigger Gingerbread software along with Sense and all. That was the limit, but after Sense was removed, the update became possible and hopefully it'll be pushed out in the next few weeks.