Twitter is becoming a serious marketing vehicle for local businesses. Everyone from your local baker to your favorite restaurant is getting on Twitter to talk to customers and draw in new ones. Just last weekend when I was driving to Vermont with my family, I sent out a Tweet asking for a good place to eat lunch. I got more than five responses, including one from a local innkeeper couple recommending two spots in town (not owned by them). That was in Brattleboro, Vermont. But that was so random. How do you even find out which of your favorite local businesses have Twitter accounts or what their Twitter handles are? Well, CitySearch is doing it for you. The local business guide is starting to build out a definitive directory of Twitter accounts and Tweets about local restaurants, hotels, spas and stores. It is starting small, with about 5,000 business listings currently tied to their Twitter accounts (which businesses can add themselves when they claim their CitySearch page), but its aim is to add Tweets by and about any of the 15 million businesses in its listings.