Currently Being ModeratedJun 25, 2013 7:12 AM (in response to RickBlack)
Not just with Mail unless you can write AppleScripts and Automator actions, but if you have Pages, Microsoft Office or another such solution you can do mail merge with those. Another product mentioned in other threads is this one:
I have no experience with it myself. You'll find other options if you search MacUpdate.com for "mail merge".