I had one final vmdk image I use for Windows dev that I wanted to use in VirtualBox instead of VMWare.

VirtualBox makes this dead simple but a few things to look out for, since you might get a BSOD that is hard to figure out:

1. Uninstall VMWare tools

2. Mount your image as an IDE, not SATA (the default when using the VirtualBox wizard)

3. Check your root .vmdk file and be sure your disk names don't have extraneous '.' suffices. I discussed this here.

Once I did these I was able to get VirtualBox running my image just fine.

Hope this helps

mike