Windows 7 RC1 has XP Mode which runs programs that work not in Vista but in XP's hands-on.
It can help small businesses move to Windows 7 easily. So don't worried about that XP application will require some changes.
There are two key elements in the core of XP Mode: Windows Virtual PC engine and Windows XP Service Pack 3 licensed.
Although they are not included in the Windows 7 version of the retail box. The purchase of Windows 7 Professional, Windows 7 Enterprise or Windows 7 Ultimate versions, will be offered a free download XP Mode.