This coming from Auburn media:

Muschamp resigns as Auburn defensive coordinator, accepts Texas offer
Posted by Phillip Marshall, The Huntsville Times January 04, 2008 4:25 PM
Categories: Football
Will Muschamp resigned today as Auburn's defensive coordinator to accept a similar position at the University of Texas.

Muschamp, who interviewed at Texas on Thursday, told Auburn coach Tommy Tuberville shortly after returning from Austin this afternoon that he had decided to accept an offer from Longhorn coach Mack Brown. Muschamp leaves after two years on the Auburn staff.

The Auburn president and Board of Trustees recently approved a raise for Muschamp that would have made his salary $425,000 in 2008.He had a two-year contract with no buyout clause. He would have been the highest paid assistant coach in the Southeastern Conference.

Here's the link:  http://blog.al.com/trackingtigers/