I have talked about flash fiction. Now I am putting my money where my mouth is, I have joined a yahoo group for writers of flash fiction. http://groups.yahoo.com/group/FlashXer/
I highly recommend this group if you want to learn to develop your skill at writing short shorts. You have to participate, or you will get kicked out.
The nice thing about it is that you not only are given prompts, but you have the chance to read others stories, offer critiques and get your work critiqued. This group will definitely help you develop writing skills.
I cannot say it enough, if you want to be a writer then write!