Silicon Valley Homebrewed Mobile Phone Club, held in conjunction with the Emerging Communications Conference at the Computer History Museum in Mountain View.
Mark Wood talked about the Cell Broadcast System, for broadcasting text messages over geographic areas. He’s the CTO of CellCast, & he lectures on Disaster Telecommunications at the University of Wisconsin. He also works with organizations such as ETSI, ITU, & the Civil Emergency Alert Service Association.
For more information, see hbmobile.org (currently down).
Edit: Here are some supplements while hbmobile.org is down: a new mailing list, a working mirror of the wiki (content dating from late February), & the mirrored meeting announcement, in which it becomes clear that the description above was swiped.