Not sure if this is borderline on the forum policy or not, but was just curious if anyone else out there had done this other than me. Its not exactly a hack, but a firmware upgrade based off of the OE linksys firmware, which enables extra features in the router. This is only available up to V3-4 i dont remember exactly, but its a great upgrade for your linksys WRT. I would recomend it.
Can be found at HyperWRT