I am running Snow Leopard 10.6.0, as far as i know im running in 64-bit mode. Ive also heard that it might work if I run the system in 32-bit mode, but this is the first time i have ever used chameleon boot loader and unlike the Darwin boot loader, i don't know where to enter the "-x32" flag. it just has options for verbose, single user, and ignore cache.