If you mean 0.96, then nope. You can only compile it as a 32 bits program. Hence, you can compile it on an x86_64 system, but only if you have all the needed libs for 32 bits. The headers will be the same though, so no problem in that department. Gentoo does this.
However, is there a reason why you do really need to install it on the system? You can just install it on the boot sector using a livecd and forget about it. Unlike with lilo, you don't need to run grub each time that you modify your grub.conf, so once installed you can just forget about it.
If you truly mean 1.96 (what's to be grub2 one day), then I have no idea, but I thought that one of the advantages of grub2 was that it compiled in many architectures, and not only x86. So my guess is that it should work in amd64.
Last edited by i92guboj; 03-27-2009 at 02:27 AM.