The MySQL Administrator is a GUI for the popular MySQL Database. I find it very useful to manage databases. It works well. I find it useful right after I give myself remote access permissions. This way I can access mysql server instances from a remote location. Most hosts ((Dreamhost allows this btw.)) will allow you to remotely connect to your MySQL server, and this helps with management if you prefer a visual representation of the database. It also comes with MySQL Query Browser which runs actual queries against your databases.
What's great is that they have a version for Mac and Windows so I can use it in either location. Usually I don't have a desktop running linux so it isn't necessary on there, but it is good to know that they also have it for Linux, in RPM (Suse RedHat & Fedora) and they have the source as well so you can build it yourself I guess.
If you're looking for it, go to MySQL Administrator and get it for your OS.