Erm sure ... irc clients connect that way ( using telnet connections ). You just have to know some P10 in order to send the proper commands. You would have to send the USER command and the NICK command followed by the PONG to the PING the server sends. Refer to the P10 guide or the rfc for more information.
IRC clients don't speak P10, unless you want to connect as a server to the undernet network ;)
Tom
