Really liking txt2go, a way of purchasing bus tickets in the UK using your mobile phone.  You simply set up an account, text to 60060, and your bus ticket is sent back to you as a WAP link.  Because you setup your account before hand, you are not bound by whatever phone carrier you have service with.  It’s perfect for kids because you don’t need cash on hand to get bus tickets, and you can’t purchase anything else with them, so it can’t be easily abused. It’s also a great service to deploy, because there’s no upgrades required to the phones or the network.  I think this would be an excellent approach to similar problems: school cafeteria purchases, bookstores, etc.

It’s all getting easier, don’t you think?