My first Android phone ever (not including my Neo Freerunner which I have yet to install Android on (but I will one of these days). I will post stuff directly related to the HTC Desire here. You should also check out the Android section as I will post everything related to Android and not the Desire there.
I have confirmed that the following codes work on the HTC Desire:
*#*#8244#*#* - GTalk service monitor