help_haiti is an auction based in the science fiction and fantasy fan community, so it's a bit heavy on offers of fanfic written to order, but there are many other things up for auction there, too. Poke around, amuse yourself, read the FAQ, and, if you feel moved, bid on or offer something.
It's a slightly more unwieldy format than other livejournal-based charity auctions I've participated in before, but time is much more of the essence, and I do admire the speed with which this format allows offers to be posted and money to be raised. Right now the organizers are working on a master list of all writing-related offers that will be more easily navigable. Meanwhile, if you're interested in any of my four offers, just click on the relevant link below and scroll until you see my familiar icon.
You can find two of my posts near the bottom of this page: a coaching session for college or grad school application essays, and a coaching session for fiction.
You can find the other two posts near the top of this page: a character named after you (also known as a Tuckerization) in my current work in progress (the 3rd Rugosa Coven novella), and the two published Rugosa Coven novellas in the available format of your choosing. (I specify available format, because otherwise some beloved smartass or another on my friends list will bid on the Book of Kells treatment.)
(And thanks to marthawells for the link! I knew there had to be a livejournal charity auction out there, but I didn't know where to look.)