I think if you book award travel for USAIRWAYS on-line there are no fees even if it's last minute. I think it must be at least 6 hour prior to departure though.
http://www.usairways.com/dividendmil...eem/awards.htm
I'm not sure if they will waive the $75 fee if you have to call.
I would probably use them in an emergency to see family if I could actually book the award res on-line.