The best tutorial for running MySQL on OS X is actually found on the MySQL website.
However, there is a really cool System Preference pane that turns on or off the MySQL server/service. This either only works in OSX 10.5 or in 32-bit mode on OSX 10.6.
I downloaded mysql-5.1.42-osx10.5-x86_64.dmg from MySQL.com and the included preference pane works on OSX 10.6.2. (Even though it says it is for OSX 10.5.)
I just installed it without uninstalling a previous version of MySQL. I was brought over to a New MBP from an older MBP running OSX 10.5 (via Apple Genius at the Apple store), which was running MySQL. So I don’t know if the older version is still there somewhere or if the /local/ folder was not brought over in the transfer.
It seems that I have avoided the issues mentioned here:
As far as editing the MySQL databases there used to be an app called CocoaMySQL. But as the link says the project has been abandoned. I heard it rumored on O’Reilley that it was because the app didn’t keep up with changes mad in MySQL past MySQL version 4.0. So CocoaMySQL can still be used on OSX 10.6 with a MySQL version 4 Database, but not with MySQL version 5.
However, there is an new app called Sequel Pro. It is available on Google Code and boast to work on OSX 10.5 with MySQL version 3-5. (I am about to test it on OS X 10.6, though the application was last updated in Dec. ’09, so it should work on 10.6.)
Of course there is always PhpMyAdmin.