Using an GSM modem or cellphone, SlingshotSMS will send and receive
text messages on behalf of your web application. It builds on the
work ofpygsm, an excellent Python library for dealing with
AT-compatible modems. What this means is that SlingshotSMS is
compatible with Mac, Windows, and Linux, and can interface with a
wide range of GSM modems and cell phones - including many sub-$200
field-ready modems. All code is available on github. Appears to
offer a JSON API. Very lightweight, but no active development at
the moment. Local server and handset required
