If anyone wants to see it in a bigger size, click Here for 1024X768
The Wallpaper is from art.gnome.org and it's a simple Blue Matrix wallpaper. It's clear that the artist was influenced by the default Panther wallpaper although he did change some little things like curves et al. I liked it. Very rainish.
You can get the wallpaper Here
For anyone wondering: the OS is Ubuntu 5.04 pre-release (codenamed Hoary Hedgehog) which is due out sometime in April.