The folks at the Outlook team blog wrote a wicked tutorial for people that have no idea on how to send out emails to large groups of people without having all those people appear on the To: line.
Email blasts that go out to each recipient individually is called Mail Merge and it’s a somewhat hard to understand capability within Outlook 2007.
So check out this tutorial. It’s well worth the 5 minutes.
Kurt Shintaku's Blog 