Also, please be advised.  Use this method at your own risk.  You are a responsible human, if you don’t feel comfortable doing this procedure find someone to help you – I am not responsible for any lost of data or corruption on your system.

Stopping MySQL
First stop the service.  You can either do this using the preference pane if you have that installed if you don’t you should be well aware of doing in from the terminal.

Skipping Access Tables
Alright – so open up a Terminal window and execute:

/usr/local/mysql/bin/safe_mysqld --skip-grant-tables

For MySQL 5 Installations do – (thanks to RY for pointing it out):
/usr/local/mysql/bin/mysqld_safe --skip-grant-tables

Running the Reset
Ok – so you have safe_mysqld running in one Terminal window, now open up another one and execute “/usr/local/mysql/bin/mysql mysql” (no quotes).  If you aren’t familiar you are opening up the MySQL console and opening the mysql table.

Write the reset query into the console as follows:

UPDATE user SET Password=PASSWORD(‘YOUR_PASSWORD’)
WHERE Host=’localhost’ AND User=’root’;

Replacing “YOUR_PASSWORD” with your desired password of course.  Once you’ve done that just exit the console “exit;” close the safe_mysqld execution and restart your MySQL server in normal mode.