A list of helpful sites related to writing. Where other sites have done a better job of listing markets etc, I've linked to them. 

 

Market Lists

TaniaWrites non-complete list of British and Irish lit mags Duotrope's Digest Ralan's Webstravaganza
Literature Training Jobs and Opportunities The Short Story Website Romance Wiki Publishers

Writing Competition Listings

(note: the Short Story Website and Literature Training in the markets listings also list comps, so I have not repeated them here)

SallyQ's Writing Calendar

Academi  Prize Magic
Writers Forum (monthly competition and Sally's article) Writers News/Writing Magazine (monthly comps)

Publishers' Guidelines

Womagwriter's Site (for women's mags) Mills & Boon/Harlequin Carina Press (Harlequin ebooks)
Accent Press/Xcite Books Bridge House Publishing The Yellow Room Magazine
MacMillan New Writing

Story Generators/Ideas/Tips/Advice/Fun Stuff

S/Cally Story Generator The Seventh Sanctum Story Generators Short Story Ideas
The Bookshelf Muse The Literary Lab The Novel Racers Resource List (see drop down box on left hand side)
Scribd.com (free books on writing) Rum and Monkey Name Generator Surname Profiler
Wikipedia List of Occupations Behind The Name Short Story Writing Tips
Ask Sally Fiction Factor NaNoWriMo
Ask Sally (Competition related) Sally Zigmond - The Elephant In The Writing Room (features very good articles on short story writing) The Literary Project (interviews with writers and industry insiders)
Fiction Factor Short Story Group Writing Tips The Critters Workshop
Writing Historical Fiction Six Steps for Writing Historical Fiction Flickr Random Pictures
Brainy Quote Ten Rules For Writing Fiction (Guardian Article)

Research/Encyclopedias/Misc

 

Windows Live Local Wikipedia Ask Oxford
Latin Phrases Ask A Philosopher Sci-Talk
Reverse Dictionary Language to Language Multi-lingual dictionary Elizabethan History
English Idioms and Idiomatic Expressions TV Tropes This Day In History