First download MySQL 5.1 and MySQL 5.0. The GA versions are the ones that have the prefpanel for starting MySQL, so you have to get both the GA and RC if you want bleeding edge with the GUI startup.

Note: a configuration of this type is meant for a machine with one user since only that one user will be able to decrypt the filevault and unlock the data file location so MySQL can run.

Unpack the contents of 5.1.22 to /usr/local/mysql.

Mount the 5.0.45 dmg package and drag MySQL.prefPane to /Library/PreferencePanes. This is how I start MySQL. Do not click for MySQL to automatically start, because it won't be able to start until after you login your filevaulted account. MySQL does appear to be able to survive through putting a laptop to sleep, so you can just put your machine to sleep a lot if you don't like starting MySQL a lot.

Alternatively, command line nuts can start MySQL like this:

Create a place for the MySQL data files in your filevault. I picked /Users/davidnorman/mysql/data and made a global configuration file to match which I put in /etc/mysql/my.cnf. MySQL 5.0 expects the configuration at /etc/my.cnf and you will find if you use the MySQL 5.0 GUI tools, the configuration section will look there, too. I consider this a harmless penalty for using RC code.

Move the contents of /usr/local/mysql/data to your /Users/davidnorman/mysql/data equivalent and run /usr/local/mysql/scripts/mysql_install_db.

Start your MySQL server through Apple menu - System Preferences - MySQL. If the status doesn't turn green, check your /Users/davidnorman/mysql/data/davidnorman.local.err equivalent. My biggest problems were from permissions, which created errors that it either it couldn't find files or they were read-only. Eventually I found

cleared it up since during other parts of the install process things were created and owned by user root or _mysql and were in a few were in the wheel group.

Set a root password if you want.