Yes - use [Google Apps for Your Domain][1]. 

It's free for up to 50 users.

[Free GAFYD][2] (as provided by [Tobbe][3] below)

  [1]:http://www.google.com/apps/
  [2]:http://www.google.com/apps/intl/en/group/index.html
  [3]:http://webapps.stackexchange.com/users/1554/tobbe