Other HTC-made smartphone users can register on the site for warranty purposes, or to get some free wallpapers and ringtones. To take advantage of the full functionality, you have to have a supported handset. Alternatively, having a ROM with this version of Sense UI installed on your device could also work, but we will wait for confirmations on that.
HTC Desire HD Specifications | Hands-on
HTC Desire Z Specifications | Hands-on