VirtualBox: upgrading from version 2.1 to 2.2 Networking problems

If you've discovered the advantages of creating virtual machines on your host PC then VMware and VirtualBox and Microsoft Virtual PC should be well known to you.
I have just upgraded from VirtualBox v2.1.2 to v2.2.0 and lost network connectivity :(
Thanks to Ben's blog here: http://ipggi.wordpress.com/2009/04/14/virtualbox-220-upgrade-networking-trouble I was able to quickly sort out the problem....

More info on Virtual PCs:
VMmare and VirtualBox and Virtual PC are all virtual machine software suites. They allow you to run a "virtual" or guest operating system inside your main operating system.
So you could run Windows XP as your main operating system while running Linux or Vista in a separate window on your desktop.

By example, a Linux user could run a Windows XP guest system and use Microsoft's Internet Explorer. I mainly use virtual machines for learning or testing. It allows me to play with and test applications on other operating systems. It also allows me to test new applications from GiveAwayOfTheDay or games from GameGiveAwayOfTheDay without worrying that they will affect my "real" computer.

See here for more info on virtualisation: http://www.vmware.com/technology/virtualization.html

See here for a comparison on VMware and VirtualBox: http://marsbox.com/blog/reviews/vmware-vs-virtualbox

Downloads:
{Note the varying sizes of each}
http://www.microsoft.com/windows/products/winfamily/virtualpc/default.mspx 63 MB
http://www.virtualbox.org/wiki/Downloads 65 MB
https://www.vmware.com/tryvmware/?p=default 58 MB