about changing ip in chatrooms

hi
i often chat in some old CGI or HTML chatrooms. in those kind of chatrooms every line looks like this:

Ice>hi everybody! (6/26 sun 02:46:45 JST, 2**-67-2*2-**7.dyn.iinet.net.au )

as almost everybody, i use proxies to hide my real IP, but some guys (which don't seem to be particulary expert with computers) can rewrite their IP like this:

Ice>hi everybody! (6/26 sun 02:46:45 JST,how are you guys?)

can anybody help me to do the same or at least give me some s***estions..

thanks,bye