By default the header Pin Nr. 7 us used by the 1-wire kernel module.
I would like to change it to a one of the 4 new GPIO Pins of an Rev 2 Pi.
To change the default GPIO pin used for 1-wire communication you can edit the
/boot/config.txt file and add this line:
x is the GPIO pin you want to use. Reboot to see the change.
Important remark: it must be exactly as indicated, without any space between parameters and values in the command: dtoverlay=w1-gpio,gpiopin=x