Mike - I believe all of the Springs houses were pre-wired by the developers, Ryland Homes and David Weekly Homes. Any alarm company should be able to activate the system for a monthly fee - ADT, Brinks, and a couple of other national alarm companies appear to be the more popular ones in the neighborhood.
If you haven't already activated your system (sorry for the late response), I'd recommend looking at the major alarm companies' website, then obtain quotes from the 2 or 3 that may interest you. There's several local contractors who try to represent the major companies, but they may not have the competitive pricing that the company can offer directly. There's also several local alarm companies that we hadn't heard of until we moved to San Antonio - we see them advertised in the mail flyers and sometimes in the paper - but, IMHO, I question if they have the infrastructure and manpower to provide adequate 24/7 central monitoring.
We pay a bit over $30/month for ADT for the system that was installed by the builder.