A year ago, AT&T Inc. learned a hard lesson at the South by Southwest music, film and interactive festivals and conferences: Thousands of smart-phone users in a limited area, all sending text messages, photos and video clips, can produce a cellular traffic snarl. Some attendees, many of them users of Apple Inc.’s Internet-friendly iPhone, noticed the wireless traffic gridlock and weren’t happy about it.

“South by Southwest draws what I call the cool-kid tech people,” said Michael Cote, an analyst with Redmonk.com. “They all have iPhones, and they all want to upload photos that they take. When the network runs slow, they get upset, and they get vocal about it. … There was a lot of complaining.”

Things should be different this year, AT&T says, when the film and interactive events kick off March 12.

“We have been doing a lot of work,” said Chris Penrose , vice president and general manager of AT&T South Texas.

That’s great. You can get your 3G and voice service up and running for one city during a special event, now would you please make it work the other 50 weeks a year in my town!!!