The cyan Nokia Lumia 900 is joining the white and black models as being available for order from AT&T.com . Can't really say the cyan model is really back in stock because the Windows Phone is listed as "will ship in 5-7 business days".
More than likely Nokia informed AT&T that the truck's ready to leave the Nokia assembly line to head over to the AT&T Warehouse. Which usually takes a few days.
While not the most ideal of situations, it is progress. For those not familiar with the Lumia 900, it's available at AT&T for $99.99 after two-year contractual discounts or $449.99 off contract.
AmazonWireless has the cyan Lumia 900 listed for $49.99 after discounts and $449.99 off contract. Downside with AmazonWireless is that they are listing the cyan model as "Usually ships in 1 to 3 weeks".
Thanks, mamacita42, for the tip!