I will guess that you are talking about the linux compilers, as the Windows version of this is supposed to work "out of the box."
You would need to make an x86-64 installation of gcc/g++ cross compiler, and make that the active g++ where you install and run the corresponding icc/icpc and ifort. I guess gcc 4.1 would be a reasonable choice. You will need to make a cross gnu binutils (as, ld, et al) and place the same glibc and gcc/g++ x86-64 libraries and headers on both your build and run systems. Several people have built g++ this way, but you will have to research how it's done. You probably don't want to try this until you have learned how to build a standard g++. You should find gcc cross compiler build instructions in a web search. Web pages under gcc.gnu.org would be the most authoritative. I don't think you'll find a pre-built version.
If the Intel em64t compilers refuse to install normally in such an environment, you still have chances. As the Intel compilers are 32-bit applications, in principle it should be possible to copy the em64t compilers (9.1 or 10.0) over to a 32-bit system, after installing on 64-bit.
I doubt the Intel compilers have been tested in a 32- to 64-bit cross compilation situation, and I would be concerned about reliability and lack of bug fixes.
