Looks like the Aztecs are staying in the Mountain West.
Big East and San Diego State officials are working on a joint release announcing a mutual agreement to dissolve San Diego State's agreement to come to the Big East on July 1, 2013 according to sources familiar with the discussions. At the same time, San Diego State and Mountain West officials are finalizing an agreement which will keep San Diego State and Boise State in the MWC as full time members. The announcements, barring any last second snags, should be made in the next few days.
Again, this is not a huge shock that the Mountain West and San Diego State would come to an agreement to remain in the league. Both sides were playing a game of chicken to get the best value from either side. Any details about any special deal for San Diego State is not known at this time. However, if we are to speculate it would make sense that the Aztecs are not getting anything similar to Boise State, unless there was a side deal for the basketball team.