Patrick Galbraith, former MySQL employee who helped write replication, came to the November 2007 Boston MySQL User Group and did a fantastic presentation on replication, including showing how to set up replication and walking us through the steps in real-time, setting up an example server.
References mentioned in the video:
Brian Aker's DBIx::Password
Giuseppe Maxia's article about federated tables -- I think that's the right one, feel free to comment if it's not.
MySQL Toolkit -- renamed Ma'atkit -- lives at http://sourceforge.net/projects/maatkit
sample my.cnf files for 2 different dual-master replication scenarios