Freenx is awesome! I'm having trouble with a yellow mouse though. Argh. After trying to debug it via Freenx client, I've determined it is caused by quartz-wm. I'm therefore trying a new window manager within X11.app, specifically xfwm4. I'll also install sawtooth for use with Gnome desktops. To do this, I'm installing Fink.
http://homepage.mac.com/sao1/fink/index.html
http://beesbuzz.biz/blog/e/2003/10/26-reasons_i_dont_like_x11app.php
http://www.macosxhints.com/article.php?story=20040710114033251
http://developer.apple.com/technotes/tn2006/tn2165.html
http://www.finkproject.org/doc/x11/run-xfree86.php?phpLang=en
http://www.mcnabbs.org/andrew/linux/macosx11/
http://www.uoregon.edu/~noeckel/TigerG4G5Setup.html
It had nothing to do with the window manager at all, but was a bug in X11 on the Intel Macs:
http://www.macosxhints.com/article.php?story=20060316124704289&query=x11 - the yellow mouse fix