MyComputerInfo script actually checks this for you Shawn.
Not the full code but something like this which also checks if the Microsoft Virtual PC is running.
Haven't ran it for awhile though so not positive if it works on all the new versions.
I wrote this about 3 years ago originally.
Code:
$VMWUser = Trim(ReadValue($HKLMSMWCV + '\Run','VMware User Process'))
$VMWPath = ReadValue($HKLMSMWCV + '\App Paths\vmware.exe','Path')
$VMWVer = GetFileVersion($VMWPath +'\vmware.exe','ProductVersion')
$VMWToolsVer = GetFileVersion(ReadValue($HKLMSCCS + '\Services\VMware Tools Service','ImagePath'),'ProductVersion')
$CVMVer = GetFileVersion(Left(ReadValue('HKLM\SOFTWARE\Classes\Virtual.PC.Floppy\DefaultIcon',""),-5),'ProductVersion')
$CVMMapper = ReadValue($HKLMSCCS + '\Services\VPCMap','DisplayName')
$CVMMapperVer = GetFileVersion(ReadValue($HKLMSCCS + '\Services\VPCMap','ImagePath'),'ProductVersion')
