I like my 32-bit Windows 7 OS and don't plan of moving to 64-bit anytime soon.  Windows 7 has lot of good capabilites, and I was hoping that the Virtual PC would support 64-bit Guest OS, but it does not. I am still waiting for Microsoft to say, "You can do it" with Virtual PC on my Laptop with 32-bit windows 7 OS. 

So I started looking around for some other tool that could help me and guess what, I found this incredible tool from Sun called VirtualBox that allows you to create 32-bit and 64-bit Guest OS on your 32-bit machine.  One of the problems I am facing with Virtual PC in windows 7 is that, there is no way for me to access my local HDD like I could do when the host OS is Windows XP.   VirtualBox fixes that problem as well.  Did I mention that it also uses the Virtualization capabilities, if you the new computers.  I love Microsoft and all that, but for this tool is a kick ass.