I just found a useful wiki called MediaOnTwitter, a contact database of Twitter addresses for journalists and bloggers.

Currently, only about half of the contacts have their segments listed, but not to worry…
It’s a wiki and it’s growing.. Fast!

In case you’re wondering, a “Wiki” is a Web site that allows users to add and update content on the site using their own Web browser. Most Wikis are created by a collaborative effort of the site visitors, which makes this one particularly interesting.

MediaOnTwitter is hosted by the PR pros at #journchat and @PRsarahevans. Currently, it lists journalists and bloggers in Australia, Austria, Canada, India, Russia, South Africa and the United Kingdom.