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.
Installation:
PSP - Simply download the attached files, unzip its contents to your PSP/Game/ folder on your PSP. And Run.
Once in the IRC, press X to pull up the Keyboard, and Start to Pull up your Options Menu.
Controls:
PSP - Once connected pressing X brings up the keyboard. Pressing Start brings up the menu. Left and Right trigger cycles through channels. D-pad Scrolls the text.