Thanks to Dusk for this post:
After the outgoing vice president of the Science Fiction and Fantasy Writers of America posted an entry at the SWFA blog, slamming professional authors who post their works online (he later toned down his wording), author Jo Walton wrote a post encouraging authors to "give away professional quality work online" on April 23 "to celebrate our technopeasanthood."
Over at the SWFA blog, the moderator, Will Shetterly, encouraged people to post links at that blog on April 23 to their online work (in replies to a special entry he'll post on that day), adding, "If you can't come up with something new for the 23rd but already have work that's free on the web, offer the link. Everyone's welcome in the IPST!"
I queried, and he clarified that, yes, he meant everyone: pro, semi-pro, and amateur writers. It seems to me that all writers who support the right of pro authors to publish their works in the manner that they wish may be interested in participating in this celebration.
If you would like an icon by which to spread the word, here are some nice ones by John Scalzi, Mary Dell (shown here), and Leigh Dragoon.