If you have more wisdom to add, please post it as a new comment. For those new to IRC, please read this project and it's comments anyway to make sure you know the basics. You are a user until made an operator, so don't try to kick ops from public channels or your client will laugh at you. All IRC addresses and/or examples are valid and accessible for the purpose of learning how to use the system, to the best of my knowledge. Screenshots were made from actual logons and were not "doctored" in any way, so you can join any channels, public or hypothetical, displayed in any screenshot here.
Internet Relay Chat is much like your instant messengers, but is devoid of spam or general security risks that other IM services not only allow but are built to accept. Typical IM services such as YIM, MSN-chat, AIM, and many others are specific targets due to their accessibility and ability to silently upload files to your computer and execute them on command without you even knowing what happened, from someone not even showing up in your chat window.
IRC is not only secure in multiple ways, but you cannot hide behind an application. If someone's there, you'll know it, and you must accept all file transfers before they are actually received. Below, I'll explain how using IRC is just as easy, far safer, and much more functional than your bloated n00b IM-client-for-dummies. For those smart enough to use Firefox, this can't be easier. For those still using IE for anything, there may be no saving you, but I'll try.
Step 1: Learn to use Firefox, or download a suitable IRC client such as mIRC
Get the Chatzilla addon here
For those so stubborn not to try the best, you can get mIRC here
I'll focus on those who know better to use Firefox than IE. Downloading the Chatzilla extension and incorporating it into Firefox is easy, simply download it and it knows where to go. You may be asked to restart Firefox or your computer, if you are not asked, restart your computer just to assure a correct install anyway. Windows likes to corrupt itself and blame properly-coded software.
Now that you have it installed, you can find chatzilla from the top by dropping down the "tools" tab in the menu-bar.