To keep the mainpage from clogging up with all the general virtualization info that’s all contained in here.
If you want to know what virtualization is then VMWare has a collection of whitepapers on the different subjects.
For a general idea on what virtualization is, look here: http://www.vmware.com/virtualization/
A Virtual Infrastructure is a bit of a different animal and the possibilities are almost limitless. To get a general idea of it you can read the whitepapers at http://www.vmware.com/vinfrastructure/
Virtualization.info has a webcast and downloadable video with a presentation on the subject: http://www.virtualization.info/2006/04/what-is-virtualization.html