<A target="_blank" href="http://www.ns-tech.com/blog/geldred.nsf/plinks/GELD-8773RU">Gregg Eldred has posted directions on how to determine which version of Domino you're running,</A> in case you forgot to write it down. He's also posted links to articles on why you might want to run 64-bit instead of 32-bit Domino.