problem starting mysql: 

sudo -u root  mysqld

120822 12:26:31 [Warning] Setting lower_case_table_names=2 because file system for /usr/local/mysql-5.5.15-osx10.6-x86_64/data/ is case insensitive

120822 12:26:31 [ERROR] Fatal error: Please read "Security" section of the manual to find out how to run mysqld as root!

http://dev.mysql.com/doc/refman/5.5/en/changing-mysql-user.html: 

chown -R root /usr/local/mysql/bin/mysql

sudo mysqld -u root