I often scan MediaBistro’s Toolbox. I find it to be an excellent recource for novice writers (like myself), but it also provides industry updates, reference links, and hints for seasoned freelancers on how to pitch certain publications. [You have to be a MediaBistro member to get full access to certain articles.]
A few weeks ago they provided advice to a travel writer on how to brush up her freelance bio.
Some other recent posts that seemed useful: Agent 101 and General Advice re: Editors
Oh, and sometimes you can learn random tidbits, like which National Geographic issue was the bestseller in 2004.