Reuters has this article that quotes Bill Gates essentially saying that blogging is the perfect business tool; I'm still waiting for Gates' personal blog. From the article:
Gates described to his audience, which included Warren Buffett, Jeff Bezos, Michael Dell, Carly Fiorina, Barry Diller and other top business executives, how blogs worked and suggested that they could be used as a tool for businesses to communicate with customers.
"It's getting away from the drawbacks of e-mail and the drawbacks of a Web site,' Gates said, "We're progressively getting better and better at it."
One of the nice things that you could do with this story is take it to the person that would make the decision about whether or not you are allowed to blog about work and show it to that person. You may also want to pick several Microsoft employee blogs as examples of what an employee blog winds up looking like. Also, find some of the rules that companies are using for their employees and assemble them into a rule set for yourself (you should personally follow Scoble's 21 rules for blogging).
Perhaps I should take my own advice and start a blog about my industry and company.