If your entire form is being duplicated except for a few fields, I wonder if your data structure is designed correctly. Is it possible you can split some of this off into lookup tables and the like?
Anyway, search the archives for 'duplicate record code' and you'll find several solutions for both VBA (preferred) and macros (changing the last word, obviously).
There's also a button for 'Duplicate Record' under 'Record Operations' in the Command Button wizard.
HTH,
David R