A leaked screen shot of some internal T-Mobile communications reveals that the carrier's BOGO promotion for smartphones is being extended again. This time, the offer will run through May 9th. The offer is good for sales through retail channels and through customer care. Through the latter, you must pick two of the same devices while through the former, you can select two different smartphones.The promotion was scheduled to expire on April 19th. A double shot of HD2, anyone?