VMWare Fusion's importer works perfectly - in the past there used to be a concern with drivers but at least by VMware 4 it just works.
2. Use unrar or http://wakaba.c3.cx/s/apps/unarchiver.html to unpack the segments
3. Open VMWare Fusion & choose import
4. Get coffee & wait for disk I/O
5. Install VMWare tools & pending Windows Updates
6. Take a snapshot so you can reset it after the timelimit sets in (as noted by Microsoft, they disallow storing data durably for more than 90 days)
There are utilities to convert a VirtualBox VM to VMware, if you are feeling adventurous :-). From my experience though, it's kinda painful (I forget what the issues were but I remember regretting the decision to convert the VM).