The tourist office in Portland, Oregon has created what somebody is calling a "twisitor centre" (or "center").
Basically, they've set up a twitter account, http://twitter.com/travelportland, and they're monitoring for tweets tagged #inpdx.
The idea is, you can ask something touristy in a tweet - eg. "what date is the Rose Festival?" - and somebody will get back to you.
The upside for them is that it is a public channel. The downside is...that it is a public channel! When I looked at it this morning they were trying to fend off the attentions of what seemed to be a local who was determined to ask awkward political questions!