I just played around with this some more...even though the number in your text message is a bunch of 1's and 0's...when the person you text'd sends you a reply, it goes to your email address that you provided.
Can you text anyone on any service or just those that have the same service providor as yours? Some like ATT only allow you to text another att person.
Maybe one of these days the agency's will be able to text their schedules to those interested from one of these websites....or a savy web designer will figure out the way to do it for them.