Pidgin does a great job of connecting all the chat & IM protocols together, and is available on Windows, Mac, and Linux (yeah!), plus it’s open-source and free! Its interface is dead-simple, but sometimes its setup can be confusing for beginners.
If you have a custom email domain for your gmail account, setting up to use Google Talk through Pidgin needs a couple extra tweaks to the settings. Follow these easy steps to get started.