Marge-IRC-Bot is a project mainly written in PHP, it's free.
Simple IRC Bot. I was intending to make this for my personal use only, but I decided to release it. Some of the parts in it, may currently not suit your needs.
Thanks to Freelancer for building the framework of this bot. You can find him on Github at GitHub.com/Visnew.
Edit config.php and set the correct settings. Type php marge.php when you are in the folder that this file is in. The bot will start.