rstothard,
Welcome to the VMware Community Forums!
I currently run VMware Workstation on Vista Ultimate x64 at home, and have seen customers run it on Home Premium and Business editions.
As for conversion from Microsoft Virtual Server 2005, you could install VMware Converter inside the MS vPC and make a Workstation compatible version. Just make sure to remove the Microsoft Virtual PC Add-Ons from Add/Remove Programs first, since that will conflict with our mouse drivers.
Regards,
EvilOne
1 - Check the documents
2 - Search the forums
3 - Post Question
And remember to award points to those who assist you.