Update: Check the comments out below from Paul who has spoken to T-Moble regarding potential delays and problems with upgrades and how they are handled. We'll find out Monday hopefully if the Desire gets launched and if existing customers have any issues picking one up.
T-Mobile in the UK have confirmed that the HTC Desire will be in store ready for purchase this coming Monday March 29. The new handset is already available to order online and via phone, but ordering that way has an estimated 7 day delivery time which indicates you'd be best actually waiting till Monday and going to pick up a HTC Desire from your local T-Mobile store.
A message was posted on the T-Mobile forums indicating that the reports of the phone going out of stock online were actually incorrect and that it was just a glitch in the reporting. Either way, it looks more likely that you will get the phone quicker if you pay a visit to the store.
The HTC Desire is an Android based smartphone that runs the Sense UI over the top of Android. The device has a 5 megapixel camera and a good sized 3.7 inch AMOLED screen allowing for some very clear images to be shown.
If getting the phone on a 24 month contract costing £35/month then you can pick up the HTC Desire for free. If £35/month is too much for you and you don't need that many minutes or texts then you can pay £129 for the handset along with £15/Month on a 24 month contract.
Other variations of phone prices and contract prices can be found on the T-Mobile website allowing you to pay more or less up front for the phone and balance it off with an 18 or 24 month contract to suit your needs.