Stateless Systems has created a new twitter visualization tool called “TrendsMap” which correlates trends in the massive fire hose of tweets with their geospatial location to overlay them onto a US map. Then you can interactively drill down into areas and see what the popular topics are. For example, if I look at the Southeast right now I see Atlanta talking about the Flooding, Damage, and emergencies related to the current rain. Over in Texas I see people talking about the autumn weather, and Florida is an even mix of Autumn, flooding, and the Dolphins.
Check it out and see what you can find.