Twitter is still the most dominating micro-blogging service out there and continues to grow at an amazing rate. There are many Twitter profiles with thousands/millions of followers and could get way better if one starts making money out of his addiction i.e Twittering.
Previously, Magpie was the only service that allowed you to make money on Twitter. Then came TwittAd. Now there are two more services that I have included in the list below. There are no confirmations of their reliability, but the following monetizing services for Twitter looks promising.