Using the onscreen menu, select the Preferences option
Press the Still/Step button on your remote control
Press the Prev button on your remote control
Press the Next button on your remote control
You will now enter the hidden setup page, and can change the player to any region or set it to region free. You can also disable Macrovision from this menu
This hack may not work on all versions of firmware. Try this hack if you have a machine that the above fails on:
Press the Setup button on the Remote Control
Key in the numbers 38883 from your Remote Control
Use the Arrow keys to change between regions or select Bypass All