Ok I'm not a controller but quite a few of our customers use this method. It's quite simple, you just get a cheap Nokia with a connecting lead for the PC (ideally with a million free texts).
When the customer sends a text, a window opens showing the details with an accept or reject option. Course the PC has to send a reply even if you can't accept the booking. It all works well apart from when they send their life story in which case the software usually can’t make sense of it and it has to be retyped in. Very good for towns with a high number of younger people i.e. those with universities.
Here’s a link that shows what you get to see. Text bookings use the same module as internet bookings but it just deals with them in a slightly different way.
http://p214.ezboard.com/fdatamaster2093frm11.showMessage?
Hope this helps.
Bill