This is by no means an exhaustive list, but these are some resources that I’ve found. If you have a link that you think should be added, please drop me an email. Also please note that these are organized in no particular order.

Communities and Forums

Evolution
This is an online writing community I co-founded in 2003. We offer forums, chat, challenges and marathons, articles, and more. We’re not limited to one genre, but welcome writers of all sorts.

Romance Divas
RD is a community geared towards romance writers of all subgenres. They have forums, a chatroom, articles, book reviews, Q&As with industry professionals, workshops by published authors … and most of all, they’re a very open-minded, supportive community.

The Rumor Mill
This is a web forum hosted by Speculations, a SFF writer’s magazine. They’re not very community-focused, but they’re a great resource for information pertinent to the speculative fiction genre — such as market updates, etc.

Hobgoblin
They’re a very small writing community, but they’re a cool group of people and well worth stopping by.

General Writing Resources

Writing-World.com
Awesome website with tons of writing articles and information on various genres and the business of writing.

AgentQuery
A comprehensive agent search engine. Very informative.

Holly Lisle’s VISION
A bimonthly writing ezine with lots of essays and articles.

Ralan’s Webstravaganza
A comprehensive market listing site for speculative fiction (science fiction, fantasy, and horror) writers.

Industry and Author Blogs

Alison Kent
Official blog of romance author Alison Kent.

Paperback Writer
Blog of multi-published multi-genre author Lynn Viehl (S. L. Viehl).

Anna Genoese
Tor Paranormal editor’s blog.

Dark Erotica
Blog of epublished erotic romance author Morgan Hawke.

Pub Rants
Blog of agent Kristen Nelson.

Romancing the Blog
Awesome romance-related blog, written by several columnists with guest appearances.

The Knight Agency Blog
Official blog of — you guessed it — the Knight Agency.

Miss Snark
Anonymous agent blog, very informative.

The Evil Editor
Anonymous editor blog, again, very informative.

Review Sites and Blogs

Dear Author
Review site run by the two Ja(y)nes; very snarky, but they’re honest.

Literary Sass
Review blog run by four anonymous writers. Again, snarky and harsh.

Evolution Writers Book Reviews
A review blog run by some of the Evolution staff.