Migrating a Windows machine is a PITA because of the way windows does it's thing but VMWARE don't help either, because it is nearly impossible to remove VMware tools.
Probably the best guide I found to migrating a windows box is http://www.kleinfelter.com/node/135. It also tackles how to get rid of VMWare tools. But unfortunately the you can't seem to get rid of the network drivers. So the article suggests switching to one of the Intel drivers. But of course you don't have network connectivity from the VM to download. So my little addition to this article is how to create your own ISO image with the drivers to load up into the VirtualBox VM.
Download the Intel network drivers from the Intel site
- Goto Applications -> Utilities -> Disk Utility
- Click New Image
- Select Partitions CD/DVD
- and 100MB is more than enough space
- Select a name for your CD "file"
- This file will be mounted and can be found in Finder.
- Copy the network driver download to it and eject
hdiutil makehybrid -iso -joliet -o [filename].iso [filename].cdr
Voila you have an ISO you can attach to your virtualbox machine and install the Intel network drivers