Replication enables data from one MySQL database server (called the master) to be replicated to one or more MySQL database servers (slaves). Replication is asynchronous - your replication slaves do not need to be connected permanently to receive updates from the master, which means that updates can occur over long-distance connections and even temporary solutions such as a dial-up service. Depending on the configuration, you can replicate all databases, selected databases and even selected tables within a database.
http://dev.mysql.com/doc/refman/5.0/en/replication.html
http://dev.mysql.com/doc/refman/5.0/en/replication-solutions.html
