Will windows 7 or 8 work with snow leopard
Will windows 7 or 8 work with mac osx snow leopard 10.6.3?
If you are talking about Windows in a Bootcamp partition use Windows 7. Windows 8 is not supported by Bootcamp.
If you are talking about Windows in a virtual machine like Parallels, Fusion, or VirtualBox, any version of Windows will work.