there really isn't no difference in installation of linux it just uses
the 64bit version of the kernel and package binaries. The only thing
I noticed when I used 64bit Ubuntu a good few months back was the lack
of 64bit versions of Java, Flash and some Windows Codecs. I believe
Adobe have now released a 64bit Flash 9 version, I think there are a
few open-source alternative Java versions out there anyways that will
work instead of the offical Sun packages. Not sure whats happened on
the Codec front. I think it was only WMA/WMV playback that was
affected iirc. Other than that the whole process is exactly the same.
I would advise you stick to Debian/Ubuntu type Distrobutions though,
a) because support will be better (bigger userbase) b) Gentoo/LFS will
be a nightmare, and SuSe/Fedora might be a bit bitchy about RPM
dependacys and buggy in places.