In addition to emailing a group of volunteers at once, it is now possible to send out text messages to a group of volunteers at once.
In the Emailer pane in MSP, type out the text you wish to send - only the Name tokens can be used in mass texts. Click the "Send" button and you will have the option to "Send as text message"!
If you have not setup an SMS account for your MSP license, the first time you send a text you will be prompted to first login to your account and open one. Text messages are a separate charge of $0.02 per message, and will only be received by volunteers with a valid cell phone number entered into the Cell field of their profile.