From Jayski.com:

Martin back to fulltime in 2009, to the #5 HMS car: Mark Martin has signed a two-year agreement to drive for Hendrick Motorsports beginning in 2009. Martin will race the full 2009 Sprint Cup schedule in the #5 Kelloggs/CARQUEST Chevy, becoming teammates with #24-Jeff Gordon, #48-Jimmie Johnson and #8ale Earnhardt Jr. It will mark his first full season of Cup competition since 2006, when he finished ninth in points. A Batesville, Ark., native, Martin also is slated to run a partial Sprint Cup schedule for Hendrick Motorsports in 2010, sharing the #5 Chevys with a to-be-determined second driver. Martin will enter 26 events, including the non-points Budweiser Shootout and Sprint All-Star Race. Mark is an incredible racer and one of the classiest guys around, said Hendrick Motorsports owner Rick Hendrick, whose organization will celebrate its 25th anniversary in 2009. He is a driver who makes everyone around him better, and our entire company is going to benefit from his presence.
I feel very fortunate to have this chance to win races and go after a championship with Hendrick Motorsports, Martin said. Coming back full time wasnt something we planned, but driving the #5 car, with all its history, was an impossible opportunity to pass up. Rick and I have enjoyed a great relationship over the years, and weve always talked about doing this. Now its working out, and were both excited about the possibilities. Martin, 49, will be paired with crew chief Alan Gustafson, who now is in his fourth season at the helm of the #5 Kelloggs/CARQUEST Chevy team. Gustafson has posted four Sprint Cup wins as a crew chief and has a history with Martin, having worked with him in multiple Nationwide Series events.(HMS PR/Markmartin.com)(7-4-2008)