the linksys wrt54g has been the target of many hacks taking it far beyond its original intended mode of operation; now going so far as becoming a personal telephone company. David DeLauro has set up an asterisk pbx system on top of the the openwrt firmware package. asterisk is a fully featured pbx system. in theory this set up could allow you to wire your whole house through one voip connection. you can even script the dialing sequence so that certain prefixes are handled by different carriers. the router has limited storage space, but you could probably use the voicemail features by mounting network storage. with enough ingenuity you should be able to pipe all of your communications and entertainment over ethernet.