"Linksys makes some fine wireless broadband routers, but one of
the best things about these devices is that their firmware is based
on Linux and can be replaced with third-party software, allowing
anyone to have the functionality of an expensive,
professional-grade router for less than $100. The GPL-licensed
DD-WRT package offers lots of enhancements over the stock Linksys
firmware and supports a wide range of hardware, including models
from Buffalo, Belkin, and other vendors.
"Noteworthy features of DD-WRT are powerful quality of service
control, which allows bandwidth optimization for specific programs
or hosts; Wireless Distribution System (WDS) with support for WPA
encryption; and RADIUS authentication for more secure wireless
connections. Check the project's wiki for a complete features
list..."