Sorry if you got your hopes up a few days ago. It turns out that the rumors were false, and the HTC One X for AT&T will not be available this week; instead, it will hit store shelves on May 6. (It turns out that Best Buy email was right, after all!)
This date is coming straight from the horse's mouth, in a statement that AT&T released to the press earlier today. The subsidized price is $199.99 on a 2-year contract, and pre-orders will begin on April 22. In the meantime, AT&T has up a dedicated page where you can sign up to receive more information about the device and other AT&T offers.
But if you just can't wait until then, Best Buy is advertising on its site that you can reserve your One X in stores right now:
There's no word yet on how much the device will be unsubsidized (at least from what I can see), but we should know soon enough.