bmt337, I was just about to post the same warning. There's already talk in the biz about what happens with FF tickets when US Air sinks, if flights can be booked with FF miles on Star Alliance partner airlines and if they'll still be honoured when US Air goes under.
It's not a happy situation. I'd be very cautious about booking anything too far out with them. Chances are very good that insurance wouldn't cover purchases made when the airline is already in this much trouble.