Upoc lets you send text messages to all your mobile friends and start mobile groups, so you can send one message that everyone gets. You can start a group for your friends, another for your family -- as many as you need to stay connected.
More:
http://www.upoc.com/about.jspMost cellular carriers use this company to handle their SMS chat groups.
I'm subscribed to FascismFile a moderated group, which occasionally carries news from DU. The moderator tends to be a little too prolific for my taste, sometimes generating as many as 10 messages per day:
Free text-information service tracking the daily disinformation and slippery slope to fascism.
http://www.upoc.com/group.jsp?group=fascism_fileHere is a great un-moderated (but low traffic) group:
The Resistance
Resistance helps progressive activists stay in touch at protests, and keep in touch between them!
http://www.upoc.com/group.jsp?group=resistance