Chuck Wendig’s Blog: The guy gives lots of free writing advice. He also has a couple books worth checking out if you wanna be a real penmonkey.
Indiebound: Writers tend to read. Support your local bookstore by ordering online from a shop in your community.
Query Shark: Janet Reid (a lit agent) helps you nail a good query by showing you the pitfalls.
Query Tracker: Online database of lit agents by genre and agency.
StoryTools: Helps you track word count.
Stephen King’s On Writing is a great tool when learning the craft of writing. By the time you’re done, you’ll be looking at your manuscript wondering why you have all of those adverbs in there.
And, of course, the old standard – Strunk & White’s The Elements of Style. Let’s all be grammar Nazis together! (Meanwhile, I’m rereading this page hoping I didn’t commit too many heinous grammatical crimes.)