Macro for different file formats

[pengyou]

I have office 2007. Almost everyone else in my school has 2003 or earlier. Is there any way that I can arrange to make 2 different files every time I save - one file for the 2007 file format and one for the pre 2003 format? I want them both to have the same name, just the different file extension for the different version. Maybe this would be a macro?