I found an interesting post in the microsoft.public.dataprotectionmanager newsgroup where it was asked if there was a way to tell what version of DPM was installed on a remote server.
Unfortunately, DPM doesn't provide a built-in cmdlet to accomplish this apparently, but a VBScript solution was provided using WMI. Of course, I had to provide a simple PowerShell solution:
PS>get-wmiobject -computername some_computer win32_product -filter "Name = 'Microsoft System Center Data Protection Manager 2007'"|select version
(I don't have a DPM environment to test, so maybe someone else can help to confirm that this works?)
So even though DPM doesn't provide this directly, we can obtain the info using the get-wmiobject cmdlet to do a WMI query.