Just tried to use an e-boarding pass at DTW sent to my cell phone. It didn't scan at the security checkpoint. I tried 5 or 6 times, with the TSA person there, telling me what to do. He said that a lot of cell phones don't work, but that generally when they're on larger devices (blackberries, pdas) they work. So, I had to go print a paper boarding pass. Oh well, worth a try. The TSA dude said that a newer scanning system is coming out soon.