The last time I looked seriously at Virtual PC 2007 was roughly two years ago, so when I heard last week that there was a new release, I decided to take a closer look. I was impressed with its speed and performance, and I had no trouble quickly setting up VMs running Windows XP SP3, Windows Vista SP1, and a couple flavors of Linux.
I’ve got more details in a post over at ZDNet:
Microsoft releases Virtual PC 2007 SP1
If you’re interested in running multiple operating systems on the same PC, it’s worth a look.
Ed Bott (@ wordpress.com) 
Ed-
On Vista 64, I tried to install Vista 64 in a VM. That didn’t work, but this was on my troubled system. Will Vista 64 run in a VM? Thanks.
peace,
mjh
Nope. You can install a x64 version of VPC on a suitable host, but you can only run x86 guest operating systems.
How would you compare it to VMWare? What would make you go one way or the other?
Ed:
Only one deal-breaker question, as far as I know: Any access to USB ports yet?
— Tim
… Oops. RTFM, eh, Ed? Sorry. I see you answered that question in your ZDNet article.
Is there anyway to get pcdos running in virtual that is running a dos application to print out to a usb printer running on the host xp system?
Access to USB? VMWare doesn’t seem to have problem accessing the host’s USB ports.
@Ed: Thanks for pointing this out. I’m a VPC user, and find the speed increase quite worthwhile.
@Michael Tock:
Yes, you can use the Microsoft Network Client 3.0 for MS-DOS. Beware – your printer will need to be able to interpret the data stream that your DOS system produces. In other words, if your program produced PCL, your printer will need to support PCL.
(You could send the data via a Unix box or other device for RIP, but that’s another matter.)
I needed Cisco VPN and it wouldn’t run on Vista Ultimate 64bit. I setup a WinXP Pro 32bit Virtual PC and installed Cisco and it worked just fine! Quite a pleasant surprise.