I wrote about Twitter many times in SoulSoup and elsewhere.
Nowadays, more and more people finding new ways to use Twitter (and other microblogging platforms) in business. Laura Fitton collected a nice list of articles on usage Twitter for Business Reading List. Some examples:

• Brave New World of Digital Intimacy, New York Times Magazine
• CEO Guide to Microblogging, BusinessWeek (6-part Special Report)
• Four Ways Companies Use Microblogging, CIO Magazine
• Five Marketing Tips for Tackling Twitter, Steve Mulder
• How Twitter Can Help at Work – Shifting Careers – Small Business – New York Times Blog
• Tara Hunt’s Tweeting for Companies 101

At Web Worker Daily Aliza Sherman wrote a post on 10 Everyday Ways to Use Twitter for Work

From Lee Leefever : Twitter in Plain English. Genius as usual!

BTW: I am SoulSoup (obviously) at Twitter!