text messages to prevent identity theft?

I think if the banks and credit card companies really wanted to prevent identity theft, they'd offer a service (i'd pay!!!) where they send you a text message every time something happens in your account.  You'd ignore most of them when you're out and about spending freely, but would easily make note of the one made when you're on the couch.

Does anyone know of services like this at their bank or outside of it??