Cory Doctorow and Charlie Stross are collaborating on a short short online called Unwirer. From the site:

This is a site where Charlie Stross and Cory Doctorow are publicly collaborating on a short story for ReVisions, an alternate science fiction history anthology from DAW books, edited by Isaac Szpindel and Julie Czerneda. [Unwirer]

Neat idea. They've only just started it so there isn't much next. They also have an RSS feed so you can keep up with each new part posted as it appears.