Hi there...
First off, there isn't an '06 Office (that I am aware of)
It is either 2004 or 2008 for the Mac
The PC versions are 2003 and 2007
But to answer your question... if you want your look to stay the same, you might want to .pdf your document
Beyond that, make sure both machines have the same fonts being used
Are you using any unusual formatting?
What actual versions of Office (Word) are you using on the Mac and the PC?
Woof, Woof - Dawg