tartansparkle said:1. Will I be able to save Office:Mac 2004 file and open it up on a Windows PC at university and print any essays etc? (don't have printer at home)
Yes, although since the DOC file format is a word processing format and not a portable document format, so whenever you switch machines/video cards/printers it's possible that some formatting might change or break (line breaks are the key issue, which can impact page breaks). This problem is the same one you could just as easily have with a Windows machine and Office 2003, unless you had an exact duplicate of the Windows PC.
It's not an overwhelming problem and often doesn't surface at all, and can pretty much be ignored so long as you use Word's built in logical page break functions (keep with next, keep together, break before...) rather than take the lazy "hit return until I get a new page" style formatting to deal with awkward page breaks.
I've seen no more problem going from Word 2004/Mac to Word 2003/Windows than moving between different Windows PCs running Word 2003. It's a "going from machine to machine" problem rather than a OSX/Windows issue.
If you really want to "lock down" the formatting, print the file to PDF on the Mac (that's built in) and then take the PDF file to the Windows machine for printing. That should eliminate these issues, and frankly is what I see as preferable unless you expect to need to edit the document on the Windows machine.