Let me introduce you one of our last Alfapeople CRM project: BoomerangSMS. This solution allows you to automatically send and receive text messages through CRM by using the Boomerang SMS API. The project consists of an SMS Router Service plus all the customisations required to get it working on any Microsoft Dynamics CRM Deployment.
Boost your productivity and plummet costs by routinely managing appointment scheduling, order confirmations and delivery times according to preset workflows. This add-on opens up a wealth of flexibility for your customers and helps you to respond to their preferences by communicating via their favored channel.
The best point of all is that BoomerangSMS is an open source project with License GNU General Public License version 2 (GPLv2). You can download it and find more information from http://boomerangsms.codeplex.com/
You can see a demo in these videos:
Boomerang for Dynamics CRM Setup
Boomerang Service Appointment Demo