Update
1500z Sunday, 28 January, 2007
Andy says it's a GO for launch about 4:00 p.m. Pacific time, 0000z 29 January.
Inflation is scheduled to begin around Noon Pacific time, 2000z 28 January.
Initially the flight will attempt to make 12,000 ft, going over Las Vegas, then New Mexico, and then up to as high as 18,000 feet in the jetstream to make the remainder of the 60 hour flight.