mIRGGI is the first IRC client for S60 3rd and 5th Edition devices.

How To Use It?
First you have to change the settings (they are automatically displayed when running mIRGGI for the first time). Write your nickname, username, realname and server. Press back and then connect.
If you want mIRGGI to connect to channels or open query windows on startup, input them to Auto windows setting.
To input text, press enter or OK button. This will bring the cursor to the input line at the bottom of the screen.
You can find more info and commands here

You can download the 5th edition version here