I've tried the help on here, but there is no place to sign into AIM when I click on the drop down by my name

I used to have it. Not sure why it's gone

<< You’ll no longer be able to sign into your AIM account from within Gmail chat since you can now add AIM contacts directly. >>

http://gmailblog.blogspot.com/2011/05/changes-and-improvements-to-aim.html