At about 2 pm a 15 year old Boy Scout left his troop and skied off Lincoln Peak,  past boundary signs, into Emigrant Canyon.  At some point he called someone on his cell phone to let them know he was lost. At that time Sugarbowl patrol sent 2 skiers to search the boundary.  They found his track and started following it.  Subsequently TNSAR was dispatched.  At about the time that team members got to the garage, the patrollers reached the MP and were able to give GPS coordinates.  Patrol at that point decided they did not need skier assistance but requested snowmobile and snowcat help with evacuation.  2 snowmobilers and the snowcat responded to Coldstream Canyon and proceeded to efficiently rendezvous with the MP and 2 patrollers at the Lost Trail Lodge and bring them back to the trailhead. The scoutmaster was very relieved to have his eaglet back in the nest and pinned him with the Survivalist Badge on the spot.