No.
[url=http://windows.microsoft.com/upgrade][img:74d9c646cc]http://img256.imageshack.us/img256/1778/win7upgradechart1.jpg[/img:74d9c646cc][/url]
http://blogs.zdnet.com/Bott/?p=1246 - better chart there.
I'm pretty sure you can use a Windows 7 upgrade disc from XP but you're still going to have to format the hard drive and lose everything on it.