According to a post at Little Green Footballs (post no. 174 on the thread about the timestamps), someone alleges that he interviewed Burkett's former lawyer David Van Os, and that Van Os said Burkett was given a call in "the first week of February" by someone with experience in the Texas Air National Guard, telling him that they had come across these documents.
The poster's name is "rod".
Hopefully the truth comes home to roost on Rather, CBS and the true source of these documents before November.