Mike Hearn and I just announced the first officially public draft of the Desktop Notifications Specification we’ve been working on. It has a few rough edges, but is there for the most part. The specification was announced on the freedesktop.org xdg-list. We’re looking for feedback and some implementations. Currently, we have a few projects who have announced their intention to use the specification, hopefully with more coming in the future.
The protocol for the desktop notifications uses D-BUS. It’s meant to be desktop-neutral, and does not define presentation. An initial GNOME notification server is undergoing development, as well as a reference implementation library. These are not yet available, however, as Mike is without an Internet connection and has not been able to submit his latest changes. These will be updated as soon as possible.