Three big cellular companies are introducing credit card authorization via cell phone at stores simply by waving it. (I think Japan and Europe have had this for years)
Twicketer could be the first truly paperless ticketing option. Just wave it at the door when you go in.
These are great innovations, and my iPhone is increasingly becoming indispensable.. But the cell phone is becoming a repository for credit card info and much more. People usually stay logged in too. Thus, if the phone gets stolen, all the info is accessible. Cell phones will be need vastly improved security, and soon.