DD-WRT

[Freecare Spiritwise]

You can turn your cheap linksys wireless router (WRT series) into an enterprise-class router with free open-source firmware. It can even boost the radio power and overclock the router's CPU. I've been using it for a month now and I'm really impressed. Not for the faint of heart - you'll brick the router if you do it wrong - but well worth the time to figure it out. I originally installed it because I hated my ZyXel router and wanted to un-retire my linksys, but the linksys didn't do dynamic DNS. The new firmware also does QoS, which I'm going to setup soon so that my Vonage line won't cut out when the girls are uploading 10 megapixel images to their MySpace pages. There's also special VoIP and VPN versions of the firmware available.

http://www.dd-wrt.com/dd-wrtv2/ddwrt.php