robin-mbp:bin robince$ file ./python2.6
./python2.6: Mach-O universal binary with 2 architectures
./python2.6 (for architecture i386):    Mach-O executable i386
./python2.6 (for architecture x86_64):  Mach-O 64-bit executable x86_64
robin-mbp:bin robince$ arch -i386 ./python2.6 -c "import sys; print sys.maxint"
9223372036854775807
robin-mbp:bin robince$ arch -x86_64 ./python2.6 -c "import sys; print sys.maxint"
9223372036854775807