Lots of agents are blogging these days, and it's informative to surf through some of these blogs to learn more about the agents, as well as the industry. Among them:
Guide to Literary Agents' Editors Blog - Writer's Digest Books offers its annual Guide with an accompanying website. This is the blog that tag-teams with that site. Great info and it's been updated regularly for the past year. Looks like it's here to stay. Definitely bookmark this one.
BookEnds - Agency blog that's been around since 2006, providing steady, lengthy posting. Wish they'd add a Labels listing in their sidebar (it's a Blogger blog).
The Rejecter - Proven blog, written by an anonymous assistant to a literary agent. Gold mine. (Another anonymous blog with lots of good scoop was Miss Snark; alas, she quit blogging but the archives are worth a surf.)
Et in Arcaedia, ego - Jennifer Jackson's blog (she also has a website) which not only is informative in its own right, but her posts are chocked full of links to other blogs (including agent blogs) that pertain to the subject at hand. Very helpful. (I've also noticed lots of agent blogs link to this blog - it's well liked among her peer group.)
Query Shark - a service to the profession, the fabulous Shark guts query letter after query letter in post after post. Not for the faint of heart.
Folio Literary Management Blog - This is a newbie (it's less than 90 days old as of the date of this post). Posts thus far are very good, and they're coming from more than one agent. Hope it sticks around.
For the Christian market, here are two agent blogs to read: Rachelle Gardner and Chip MacGregor. Chip MacGregor's at MacGregor Literary; Rachelle Gardner is at WordServe Literary.