How to chage to 64 bit from 32 bit
I can't find a place on any of the system press to switch to 64-bit mode.
Lion runs in 64 bit mode and requires a 64 bit processor. If you're running Lion you're already using it.
See for yourself: check About this Mac, More Info… System Report > Software.
Macs that use the 64 but kernel: http://support.apple.com/kb/HT3770