The lead developer of VirtueDesktops has discontinued work on the project. Others may take up the reins, but that's still to be decided. Eventualy, Apple will offer similar technology in Leopard, called Spaces, but we wont' see that until October.

There is similar program called Desktop Manager that you can use until Leopard ships.

To remove VirtueDesktops, start up in Safe Boot mode by holding down the SHIFT key at startup. This prevents any applications from starting up at login. Once you've safe-booted, then go into your Accounts preference pane and in your user's login items section, remove VirtueDesktops from launching at login. Then delete the application from where-ever on your hard drive you strored it. Then log out and back in again (or reboot).