Next to formatting, Promotion seems to elicit the most visceral reaction from self pubbers.  This reaction can be anything from sudden eye twitching, to soft whimpering sounds.  Self promotion seems to be one of the biggest hurdles for writers, but help is at hand.  Here are some wonderful sites and suggestions to make this process a little less painful. 
Goodreads - A book recommendation site for readers and writers.  They have a wonderful Author Program that allows you to post writing and take part in giveaways. 
Shelfari (by Amazon) - A gathering place that enables readers and writers to connect with each other. 
Wattpad - A community for readers and writers.  You can post writing, read, vote and chat.
Library Thing - Touted as the largest library in the world, it is a place where readers and writers can catalog their books. See the Library Thing Author Page to find out how to best use the site.
A couple of great book promotion sites:
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Fellow author T.K. Richardson has compiled a comprehensive list of resources for writers on her new site, The Writer's Resource Directory.  This is a wonderfully informative site.  Be sure to add this site to your toolbox