Seems to me there are a lot of really talented folks here at PC, thought it'd be good to maybe create a thread where we can share resources that are helpful.
Some off the top of my head:
Zoetrope Virtual Studio Home - the virtual studio of Francis Ford Coppola, they have feedback forums really nicely set up for screenwriting, poetry, short stories, music, and even acting, etc. For the writing studios, you have to review 2-5 entries from other people for each 1 you post of your own. It works great because it keeps the flow of feedback going. Entries are also eligible for publishing in the print version of Zoetrope magazine. I think it's a cool place.
Self Publishing - Lulu.com - lots of cool options for self-publishing, I know a couple of authors who have had a great experience with their services. A lot of self publishers are thinly veiled scams, but lulu.com is fairly set up I think.
Free Screenwriting Software by Scripped.com - an online screenwriting program that formats your script as you type, sort of like final draft, except it's free. And you can log into your script in progress from any computer. They have taken extra precaution that no one has access to your work in progress but you.
http://www.wordplayer.com/columns/welcome.html - a great series of articles on the art and craft of screenwriting. I've read many many many books and articles and this series is one of my favorites.
Songwriting Tips & Tools - The Muse's Muse - tons of excellent songwriting info, be sure to check the archives as well as current columns.
ok i have a ton more than that, but my links aren't very well organized right now, these are off the top of my head, but I thought I'd get a thread started!