If they are quality targeted Twitter followers, you can sing up for paid per tweet programs and send messages out several times daily. That is how big celebrities utilize their following to promote products...often times reaching several hundred dollars per tweet! Kim Kardashian makes more than $10,000 per tweet this way...well, at least her account does.
Other good methods to make money with a Twitter following is to post quality tweets with affiliate links occasionally inserted in there. Cloak these links using a URL shortener that pays-per-click and you have 2 revenue sources for each tweet!
Another powerful tool is to direct those targeted followers to niche related pages/products. You can really tap into this stream of followers by getting them involved in your CPA ventures. I actually do this with several different Twitter accounts related to specific niches. I make a few cents on the URL cloaking when they click and build e-mail lists when those followers visit websites with CPA offers.
Good luck with your Twitter project as social media marketing is a lucrative, thriving industry in itself. Make this a regular part of your IM repertoire and you will have a diverse income stream.