Check out the guides for client specific info
Pidgin - An all purpose chat client with nice GUI, supporting a lot of different chatsystems - the guide only deals with the IRC part.
HexChat - IRC only, not as handsome a GUI
mIRC - Oldschool IRC client, can do incredible powerful stuff when used on more regular IRC channels/servers than Twitch's.
Note : If you had an IRC client working before and it doesn't now - follow the steps below (Guide made by Rodr1c)
Twitch changed their settings for connecting via IRC clients. Follow the directions below to get your oauth token needed instead of your password. Click the link below if you wish to see the full post by Twitch Support.
http://help.twitch.tv/customer/portal/a ... twitch-irc
Prerequisites
In order to connect to Twitch IRC, you must have two pieces of information:
- The name of channel that you want to join.
- A Twitch account.
Once you have that information, you can then take it to connect to Twitch IRC with the following bits of information:
- The server name to connect to is: irc.twitch.tv.
- The port to connect to is 6667
- SSL is not supported for Twitch IRC.
- Your nickname must be your Twitch nickname
- Your password should be an OAuth token. You can get your oauth token here: www.twitchapps.com/tmi (Thanks Andrew Bashore!)
- An example "password" using this method would be "oauth:asdasd234asd234ad234asds23" without quotes.