I find that being limited to 4 windows in Microsoft's version of VDM (Virtual Desktop Manager) is being too controlling, so I did a search and found that this is the easiest to use Multiple Desktop Manager out there, and its FREE (as in beer).  You can have as many desktops as you want, and configure hotkeys to switch desktops or just mouse over to the right or left.  I hope you get as much use out of it as I do daily.

http://virt-dimension.sourceforge.net/

I don't have a cool avatar yet...  Sorry, maybe I'll post my Laptop Specs...

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HP ZV6000US AMD64 3200+ 2.0GHz
2GB RAM, 60 GB HDD
Dual-Booted Windows XP and Kubuntu 7.04 (Feisty Fawn)