ACG - are you using an air compressor meant for cars? How high a pressure is it meant to go? I'd be afraid to leave it unattended in case it blew the tube and tire off the rim.

When you're at the LBS, I would recommend investing in a floor pump. SO, much better and easier and accurate. We have one in the car so that tires get pumped up once we're at the ride and it's elevation. Elevation may not be a factor for you, but yellow keeps dragging me out to high altitude rides . . . oh wait, I just suggested one at Donner Pass. Oops.