You ether pay for your "own" domain name, host or what ever.. and some shell's have whats called v-hosts, they are bounded to IP addresses, so the host you see on irc is payed ones.. or maybe if they are lucky they have friends that can give them a v-host to there IP's. how ever if you thinking of get your self a v-host or domain name, then you need to have your own IP address, a modem user would have big problems bind there IP to a host, im shure you find shell's that suport it if you use google or other search engine, the shell's that suport it often need you to set up a bouncer and then bind the v-host to the IP.. im shure you find much more explained information about this if you search the webb, i just explained it really short..

good luck with your hunting..

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you can bind what IP you want to free www hosts, but you wont get that host when connect to irc tho, its just a forward from that
www.address to your IP..