Chip MacGregor is a veteran in the industry, and his blog offers "publishing tips, insights, and wisdom from a seasoned pro in the book business". Chip currently runs MacGregor Literary. His clients include Brandt Dodson, Susan Meissner, Will & Lisa Samson, Ann Tatlock, Chris Well, and many more.
Recent entries have covered contracts (in detail), agents (of course), bad poetry, and lots more. Check the blog out here.