YamaIRC is an Internet Relay Chat(IRC) Client for the Zune HD and PSP devices. It currently supports all the basics of IRC from PM’s to Actions(/me) to Joining/Parting Channels. It features Multi-Channel support, Selectable User Lists, Built In OSK, MyChannel Private Messaging Window, New Message Alerts, and more.

http://forums.qj.net/psp-development-forum/174565-yamairc-beta-1-internet-relay-chat-client.html