IMessage/iChat: Can't connect Apple ID?

So I never used iMessage on my computer before. I tried and it said I needed to update my software so I did, and iMessage became iChat. However, when I open iChat it simply connects to my gmail account. There's no option for me to plug in my Apple ID to get my iPhone number contacts in there. I've searched and there simply isn't a place for me to type in my Apple ID! It's frustrating. Any help would be appreciated. I already tried the lame Apple.com generated guide to using iMessage on OS X (http://support.apple.com/kb/ht5538)

You should use the same email that you use in the iPhone. Just go to the preference on your computer and delete the current one and the one want. I would go to iCloud and do it.

To clear something up: iMessage is a service, and iChat is an application that uses various chat services. They are completely different things.

You can't use iMessage in iChat. You need Mountain Lion or later, where iChat is now called Messages. To set it up, you open Messages (should be in Applications folder), press cmd+comma to go to the settings, and there's a button somewhere to add a new account. Then type in your login credentials, and you should be set.