I've posted the steps/fixes to get a 64-bit NS/Cocoa Emacs 23.1 working for Snow Leopard on my blog at http://blog.fac9.com/index.php/2009/08/30/building-a-64-bit-emacs-on-snow-leopard/ . I've been using it for a week without problems.
Feel free to roll those changes in, I haven't contributed to any GNU projects before so I'm not really sure where to begin making a patch / dealing with copyright assignment.
Which brings me to: is there a page somewhere with the steps on how to get involved /w emacs dev, what the contribution protocols are, who owns what area and such? I'm interested in improving Mac and Win32 support.