Sequel Pro is a must-have free app if you want to access a MySQL database from a Mac. It can connect to remote servers over ssh, edit table structures, dump and restore databases. It even has a great query editor that saves a history of queries and favourites. This is an app that does a ton of things, with a good looking user interface that's a pleasure to use. The only way Sequel Pro could be any better is if it also accessed PostgreSQL databases.