Linux on a Linksys wireless router
This is one of those projects I’ve been tempted to undertake for some time… Newsforge has an article on Linux on the Linksys wireless WRT54G and WRT54GS routers. The distribution designed for it is openwrt which is an embedded linux flavor.
Among other things, this install would give a full interactive linux system with remote shell (telnet/ssh) access in addition to the traditional web based configuration. But it’s possible to do other things such as install, Snort, Asterisk, or a mini-sendmail install. Further, you could setup and administer VLANs for each network port on the router.
Of course it would also void your warranty so if you do this go in with eyes wide open.
They give a nice tutorial on getting OpenWRT installed if the idea strikes you.