Five Best Instant Messengers
Check out this Lifehacker post about the Five Best Instant Messengers. I often find myself forwarding this link to my friends when they tell me that they're still using AOL's Instant Messenger application (complete with advertising).
You can find upgrades to your current IM situation regardless of your operating system. I like Adium for OS X, and Digsby for Windows. When I'm not on a personal computer, it's the web application Meebo for me. All of the apps mentioned can do multiple protocols at once, meaning that I can be connected to my friends on Facebook, GMail, Yahoo! IM, and AIM all at once.
You can find upgrades to your current IM situation regardless of your operating system. I like Adium for OS X, and Digsby for Windows. When I'm not on a personal computer, it's the web application Meebo for me. All of the apps mentioned can do multiple protocols at once, meaning that I can be connected to my friends on Facebook, GMail, Yahoo! IM, and AIM all at once.