Scott M. Sandridge

The Elements of Style, Fourth Edition

On Writing 

How to Write Science Fiction & Fantasy

The Writers Complete Fantasy Reference: An Indispensable Compendium of Myth and Magic

Aliens and Alien Societies (Science Fiction Writing Series)

Science Fiction and Fantasy Writers of America, Inc.: Their Writer Beware page is a definate bonus.

Critters Writer's Workshop: A critiquing workshop ran by A. Burt, and possibly the best one on the Net.

Better Fiction: another good critiquing workshop for writers.

The Lost Genre Guild: for writers of Biblical speculative fiction.

Ralan's Webstravaganza: where you'll find tons of magazine, book, and antho markets to submit to.

Tangent Online and SF Reader: two great places to find reviews.