Ten thousand small and mid-sized businesses will have a new and potentially powerful online marketing tool next month. Twitter announced today that it has partnered with American Express to roll out its self-service ad platform to the first 10,000 businesses that register starting tonight.

“So many hundreds of thousands and even millions of small businesses have been using Twitter effectively for years already,” Twitter CEO Dick Costolo told Ad Age. “So we’re opening up our ad platform to all these folks as a mechanism for them to amplify the value they’re already creating.”

For a business to qualify, they must use or accept American Express. In return, American Express will provide the businesses with $100 in advertising credits toward bidding on promoted tweets or promoted accounts. The self-service ad platform will allow users to create and manage their advertising campaigns without working with a sales representative.

While eMarketer projects that Twitter’s ad revenue will grow from $139.5 million in 2011 to $259.9 million this year and $540 million in 2014, there is mutual benefit for small businesses using the ads effectively. Glennz Tees, an online T-shirt retailer that participated in Twitter’s winter pilot of the program, used the platform to promote an appearance of one of their T-shirts on the show “The Big Bang Theory.” The company's advertising helped to double holiday sales and tripled Twitter followers.

Do you use Twitter for your small business? If yes, will you consider advertising? Share your thoughts in the comments.