The State of Michigan signed on with Microsoft last year for a software license: it includes use of Bing Maps Enterprise and to-be-collected 12” imagery. It’s officially called, “Bing Maps for Enterprise with Imagery Acquisition.”
The state is covering 30% of the cost and counties are funding the remainder. The cost per square mile? $40 per square mile - quite a good deal by all estimates. (Six inch resolution buy up is an additional $79 per square mile.) The deal is for Microsoft to select photogrammetric firms to fly 1/5 of the state each year for the next three years, leaf-off beginning early this year. There are restrictions: the data can not given away or sold, but it can be used for government in-house and public facing apps (such as in ArcIMS site hosted by counties). The imagery is not in the public domain.
The Michigan Center for Geographic Information and Office of Technology Partnerships Website has all the details on the Agreement, endorsement letters, FAQ and other documents; none have dates. I contacted Microsoft for comment on this or any other efforts like this; they basically had no comment.