Woody Paige and his big old head are reporting that Peyton Manning and his big head plan to play next season for the Broncos.  His return is however linked to whether or not he passes his annual physical:

According to three trustworthy sources, Manning wants to return to the Broncos, but won't and can't make a final decision until he takes an annual physical examination mandated by his contract. Last year, the test results were learned at the beginning of March. The Broncos have requested that Manning let them know his plans by March 9 — the day before teams must exercise their rights on veteran players under contract. Manning, who turns 39 on March 24, is due $19 million next season.

The Broncos have said publicly they want Manning back.  So right now it looks like he'll be back under center for the Broncos next season, assuming of course everything goes well with his physical.