This is what I got from there web support:
Thank you for contacting Sprint Customer Service. I am happy to assist you regarding the launch date of HTC Touch Diamond phone.
The launch date of HTC Touch Diamond phone is September 02, 2008. Once it is launched, you can purchase this phone by calling our Telesales at
(800) 777-4681. Alternatively, you may visit the nearest Sprint Store to purchase this phone. To locate the nearest Sprint Store, please click on the link given below:
www.sprintstorelocator.com
Thank you again for contacting Sprint Customer Service. We appreciate your business.
Sincerely,
Abel R.
Sprint Customer Service