XPM (XP Mode) from Microsoft is a tool to lure corporate users encouraging them to start using Windows 7, for running applications that are not natively compatible with our good old friend Windows XP. Most of the applications for XP are `expected` to be compatible with Win7, but as an additional guarantee this feature has been released.
I was trying to install Microsoft Visual Studio 6.0 on my machine running Windows7 Professional (64 bit). I got the Program Compatibility Assistant warning me that “Visual Studio has known compatibility issue with this version of Windows.” :| I decided to give XPM a try and downloaded the Windows XP Mode (470 Mb) and Windows Virtual PC (10 Mb). Downloaded and installed both the programs as per the instructions given in this link. The installer wanted the Virtualization support setting in the BIOS to be enabled before continuing with the installation.
After installing, clicking All Programs > Windows Virtual PC > Windows XP Mode displays the familiar screen of Windows Virtual PC booting Windows XP virtual machine. It was a pleasant surprise to find the Win7 partitions getting displayed on opening My Computer. All the files in the host OS (Win7) are now accessible from the guest OS (WinXP).
Installing Visual Studio in XP:
Copied the Visual Studio ISO Image to the Win XP desktop, mounted the CD image using PowerISO and installed Visual Basic. The Win7 start menu lists all products that are installed inside the XP virtual machine – which is super cool. Due to that I was able to see the Microsoft Visual Basic 6.0 (Windows XP Mode) entry under All Programs > Windows Virtual PC in Win7.
On clicking the VB shortcut in Win7, the application launched instantly (with the XP title bar) as a virtual application inside the Windows7 desktop. What a great way to seamlessly integrate Operating Systems!
Click the screen shot to get a better view. Cheers to Virtualization! 
Running Visual Basic 6.0 (in XP Mode) in Windows7
To learn more about installing and setting up Windows XP mode in Windows 7 go here.