Littler, 31, has spent his entire professional career with the Reds, racking up 329 appearances, scoring 112 tries.
He joins fellow ex-Salford men Steve Nash and Robbie Paul in the Centurions squad for the 2011 season.
The Ireland international said: “I think everyone has known that I’ve been talking to the club. It’s been a long process but I’m glad it has come to fruition and I can’t wait to start.
“Where I will play is up to Ian but hopefully my form will warrant playing. I can cover any of the back row positions or centre, so hopefully I will get a shot at that.
“I’m friends with a lot of the lads and it should be quite easy to slot in there.”
Littler made 26 appearances for Salford in Super League last season, but his most prolific seasons with the club were their promotion campaign of 2003 and their title winning National League 1 campaign in 2008.