The Inq claims the Radeon X1950XTX will be launched in mid August.
X1950XTX, or ATI's R580+ is set to be launched at a games convention on the 23rd of August. The samples are going to be ready even earlier, in the middle of the month.
Production cards in volumes are expected some two weeks after the sample phase and so they'll be available to buy in the last week or August.