Three UK have announced this morning the 2.3 Gingerbread update is now available to HTC Desire HD customers (just to avoid confusion this is ONLY for the HD and NOT the original HTC Desire).
This is a free OTA (Over the Air) update so will not need a cable to install.
If you have not already had the message then check under Settings and manually search for an update to make sure you get access to that gingerbread goodness that 2.3 has to offer you.
This update is for Three branded HTC Desire HD devices, anyone with unlocked sim free or handsets supplied by another network might have a longer wait or already be using 2.3 before now
Link: Three Twitter