Identify new Entries

I am hoping someone can point me in the right direction.

I am trying to use VBA to run a script to identify new entries from a list of Entries. The list has 6 fields that make them unique. I would like to take the updated listing and compare each entry (row) to the master list. Where new entries, or revised entries are found, I would like to append the entry to the master list. In the event of a revised entry, I would like to retain the original entry and mark it historical and append as a new entry.

I am using Excel 2007.

Any help would be appreciated.

Thanks!