As you may know, it's become custom recently for the folks who have memberships (attending or not) to the upcoming Worldcon to get free copies of most of the nominees, so that they can all be checked out before it's time for voting. Even better this year, however, is that all five of the nominees for the Short Story Hugo are already free on the web, so why not have a look and enjoy?
“The Cartographer Wasps and the Anarchist Bees” by E. Lily Yu (Clarkesworld April 2011)
“The Homecoming” (PDF link) by Mike Resnick (Asimov’s April/May 2011)
“Movement” by Nancy Fulda (Asimov’s March 2011)
“The Paper Menagerie” (PDF link) by Ken Liu (The Magazine of Fantasy & Science Fiction March/April 2011)
“The Shadow War of the Night Dragons: Book One: The Dead City: Prologue” by John Scalzi (Tor.com)
Thanks to John Scalzi's blog post on the subject for the info!