MySQL Preference Pane control for MySQL installed via Homebrew
Solution 1:
See my answer to your question at superuser.com.
Solution 2:
My understanding is that you can't get the MySQL Preference Pane via homebrew. But if you download the 64-bit DMG file from MySQL's community server download page, it includes an installer, preference pane, and startup script.
See also the answer to this StackOverflow question, about installing MySQL on Lion.