Russo signed a five year deal in August-September 2008 with SiriusXM.
Francesa's current contract runs out in February 2014 (after the NY-NJ Super Bowl at MetLife Stadium in E. Rutherford, NJ).
Originally he signed a five year deal with the FAN at the same time as Russo did with SiriusXM, but had it extended a few months ago to go through the Big Game.
Michael Kay's contract with ESPN Radio runs out later this year (2012). Negotiations are ongoing. Mushnick/NY Post seems to think he's staying while Raissman/NY Daily News isn't so sure.
The reason "Mike's On" ;D from 1-6:30pm is so WFAN can boost their ratings in both middays (10am-3pm) and afternoon drive (3-7pm). A few years ago, Neil Best had a piece in Newsday with dayparts broken out: Francesa had excellent numbers in the 1pm and 5pm hours with Males 25-54. Those may have eroded slightly over the last year or so with ESPN Radio making small inroads, especially in the younger demo of Males 18-34.