Only the European HTC Sensation can be unlocked via the HTCDev website at the moment, but it's a start.

Link: http://htcdev.com/bootloader/



As expected, HTC has released its web-based bootloader unlocking tool today. The Taiwanese company said that after listening to user feedback, they have decided to allow the HTC bootloader to be unlocked for any new 2011 phone models.

According to the official HTC Dev "Unlock Bootloader" page, at the moment, the only device to work on the new bootloader process is the HTC Sensation (EU) FOTA 1.45.301.2 device, though it shows that both the HTC EVO 3D (Sprint) and the HTC Sensation 4G (T-Mobile USA) handsets will be unlockable soon. They do mention that some models may not be unlockable due to operator restrictions.

Unlocking the bootloader allows users to customize software on their devices. It was only in May this year that HTC CEO Peter Chou announced via their Facebook page that all of the company’s future devices would be open, saying “There has been overwhelmingly customer feedback that people want access to open bootloaders on HTC phones. I want you to know that we've listened. Today, I'm confirming we will no longer be locking the bootloaders on our devices. Thanks for your passion, support and patience.”

As is the norm, HTC makes it crystal clear that if you choose to unlock your bootloader, not all claims that you make based on your warranty may be covered. They also make it clear that unlocking the bootloader will not unlock your SIM. (Source)