A great tool for dead-centering is available from Micro-Mark. It is
a laser guide which is gripped in the chuck and projects a red dot
onto the workpiece:

http://www.ares-server.com/Ares/Ares...oduct&ID=83191

Of course, you will still need to centerpunch and/or use a center
drill as outlined in the other responses. The laser guide just
assures that the drill is aimed EXACTLY where it should be!

--
H. L. Law