You can strip out the bot stuff and just use it as an out bound IM sender. Either way, the "bot" or "client" as you like to say, has to log in, maintain a connection, and listen for TOC traffic and respond accordingly. I've attempted (although its not great) to seperate the TOC protocol stuff from the bot/client itself. So stripping the bot stuff shouldn't be difficult.
In terms of using this as a replacement for a GUI chat client, I wouldn't recommend my code or PHP for the job. You might look at GAIM since its open source. You could add your features to their GUI client and go nuts with it...