I found a very neat solution to negate having to reboot into Windows. It is possible to login into a VMware guest OS in full screen directly from the GDM login screen. I can now log into Gnome or Windows XP after I boot up Linux. After using Windows XP I shut down the VMware guest OS, close VMware and I’m right back at the GDM login screen in about 10 seconds or so. Here is a link to the howto.