Ye ask, and ye shall receive

<a href="http://zmax.org/q3a/router.htm" target="_blank">Here is a good one</a>

<a href="http://guides.barrysworld.com/quake3/TweakingQ3/" target="_blank">Another good one</a>

<a href="http://www.pcshooter.com/hardware/linksys.html" target="_blank">Another good Linksys router related one</a>

<a href="http://ucguides.savagehelp.com/Quake3/connection.html" target="_blank">A good one for Quake 3 related stuff</a>