Openfire
What is Openfire?
Openfire is an XMPP protocol chat server. You can use it for secure communication with family and friends. The protocol can run over SSL and does by default.
You can also use it as an IM gateway via the kraken plugin. That means you register you different users (AIM, Yahoo, GTalk, MSN, etc.) and all of your buddies show up in the same list just by you logging into your chat server. Why would you want to do that? Because when you connect to a wifi hotspot and log into instant messaging such as AIM, your password gets sent as clear text and anyone sniffing on the network will be able to see it. Using your Openfire connection will be encrypted with SSL so even though you're logging in on a wifi hotspot your password won't be easily obtained. The connect is unencrypted, however, from Openfire to the AIM servers because that is the nature of the protocol. That is the case with most of the chat protocols.
How to install Openfire
more to come...