I just came across the first speakers bureau blog I've found yet. Written by Yvon Douran, president of Keynote Resource, Corporate Event Planning is off to a promising start. So far, she's posted about determining a speaker's worth, event planning basics, and what is expected for different types of speaker roles (keynotes, plenaries, etc.). And she has a colorful family history, which she blogs about on Speaking of Fletcher Christian, her ancester who incited the mutiny on the HMS Bounty in 1789.
If anyone knows of other industry-related blogs, please let me know. The only other supplier-side blogs I've found so far are Grass Shack Events and Media (a production company) and Something Extra from SNC Destinations—both of which are great reads. Still no bona fide planner blogs yet, though I'm still looking.