Do you have first-hand information that needs to get out to the public, but you’re afraid you’ll lose your job if your identity is revealed? If so, I have a suggestion for you: talk to a journalist.
I would specifically recommend talking to Jonathan Ahl. He’s a reputable, experienced journalist. He, unlike bloggers, has a lot of case law backing up his right as a journalist to protect anonymous sources. He has had professional training in protecting a source’s identity. He can help you get your information out (assuming it’s true and newsworthy) in a constructive way without compromising your identity. Naturally, you must have first-hand knowledge (not merely a rumor you heard) and be able to sufficiently prove your allegation to him.
Here’s what does absolutely no good: posting anonymous comments on blogs with no supporting evidence. First of all, if you talk to a blogger, there’s a pretty good chance we’re not going to be able to legally protect your identity if we get subpoenaed (short of going to jail for your sake). Secondly, no one has any reason to believe you because you’re just a pseudonym with an unfounded accusation, for all we know. Third, if what you post is libel, any reputable blogger will remove your statements anyway.
And I have another piece of advice: if you do contact a journalist, don’t do it from work. Don’t send a whisteblowing e-mail from a company computer. Even if you’re posting anonymously or from a Hotmail or Yahoo account, your company knows what was written from which computer in their network, and they know who was logged on that computer at what time. Trust me, you will be discovered. If you’re going to write an e-mail, at least write from home; a public computer at the library would be even better.