HTC Provided Unlock solution for the Droid Eris, the HTC Hero, the HTC Legend, and the T-Mobile myTouch 3G and 4G flavors. Nice to see HTC throw a couple of oldies in there but this ultimately begs the question: are any of our readers actually still using any one of these devices? Do note that the Hero unlock tool is for the GSM versions only, and you may have to flash a new RUU (HTC-speak for a full OEM ROM) to do the deed.
Source: HTC dev