i got it from my university. its not free and actually costs 1000$ a copy but you could find it in p2p networks
there is a main kernel mathematica binary "MathKernel" that you run with qemu-1386 with this command
/home/QtPalmtop/bin/qemu-i386-static /usr/local/i386-linux/lib/ld-linux.so.2 --library-path /usr/local/i386-linux/lib /path/to/MathKernel
you need to put the i386 libraries required by MathKernel in /usr/local/i386-linux/lib
you can find these dendencies by
ldd MathKernel
in your linux box
tovarish