I have a Linksys WRT54GS v1.0 that I installed http://www.dd-wrt.com

I'm not using it right now but I wrote some scripts to package my own
dd-wrt release.  I only did this because I wanted to keep the LAN and
wireless LAN networks separate and therefore had to manage the box
myself.

Firmwaremodkit lets you unpack the dd-wrt image.  I then made a couple
of modifications and would repack the image.  The scripts here do
that.

They may be of use to someone.