I want to install the aim-1.5.286.tgz file.
How do I go about doing this??
Please list step by step instructions

As far as I am aware "tgz" files are either
A) Tarballs, with source code or pre compiled binaries inside
B) Slackware packages ( not installable on Kubuntu )

I believe Kopete is able to be used as a client on the AIM network, and will also have integration with KDE ( visually consistent + obeys same file associations )