Delta now accepting cell-phone boarding passes
Phones can be used to check in for flights and also at security checkpoints and gates. Security agents and Delta employees presumably scan an image of a barcode that matches up with your boarding pass.
Continental and Northwest have similar pilot programs in place (pilot, ha!!!) so it appears that it may only be a matter of time before we’ll all be able to use our phones as boarding passes, at which point I’m absolutely certain that the money the airlines save by not printing out paper tickets will be passed right along to all of us, the hard-working consumers. Right? Right?
Treo Central via textually.org