ESPN's Joe Schad tweeted this morning that Boise State would be joining the MWC today and the conference later released a statement making it official. There has since been a press conference with Commissioner Craig Thompson and other officials, and MWC Connection has a nice breakdown of the event.
If you're not familiar with SB Nation's site covering Boise State athletics then you should head over to the fantastic "One Bronco Nation Under God" for more coverage.
Welcome Boise State University to the Mountain West Conference!
It should also be noted that Nebraska has officially joined the Big 10 and that further expansion involving the Pac-10, Big 10 and even the SEC seems likely. Stay tuned...
**Update** - MWC Connection also has a post outlining the pros/cons of further MWC expansion...