Tomato is a small, lean and simple replacement firmware for Linksys' WRT54G/GL/GS, Buffalo WHR-G54S/WHR-HP-G54 and other Broadcom-based routers. It features a new easy to use GUI, a new bandwidth usage monitor, more advanced QOS and access restrictions, enables new wireless features such as WDS and wireless client modes, raises the limits on maximum connections for P2P, allows you to run your custom scripts or telnet/ssh in and do all sorts of things like re-program the SES/AOSS button, adds wireless site survey to see your wifi neighbors, and more.
Routers that are known to work with Tomato:
Linksys WRT54GL v1.x, WRT54G v1-v4, WRT54GS v1-v4, WRTSL54GS (no USB support)
Buffalo WHR-G54S, WHR-HP-G54, WZR-G54, WBR2-G54, WBR-G54, WZR-HP-G54, WZR-RS-G54, WZR-RS-G54HP, WVR-G54-NF, WHR2-A54-G54, WHR3-AG54
Asus WL520GU (no USB support), WL500G Premium (no USB support), WL500GE
Sparklan WX6615GT, Fuji RT390W, Microsoft MN-700
This will not work on Linksys WRT54G/GS v5 or newer WRT54G/GS routers.