This page will provide links to writing markets, guidelines and competitions. I'll aim to update it now and then.
Short Story Markets
The Weekly News
The People's Friend
Flash Fiction Markets
Flash 500: Quarterly competition for fiction of 500 words
Flash Stories: Quarterly competition of up to 500 words
Flash Fiction Online: Stories 50 to 1000 words.
Vestal Review: Fiction up to 500 words.
Txtlit: Story in 160 characters texted by mobile phone (monthly themes)