Is there a centralized place/software where I can store all my chat logs? I switch computers a lot, and want one place to sign into to do all my chatting. I currently love Gmail because it can log all my AIM conversations as well, but I also chat through Facebook and other IM services and want them logged. I also used Meebo for a while, but there's no way I can export and save these logs.
Try using Trillian. It will let you login to mutliple chat clients, including g-chat, aim, facebook, twitter, etc. and gives you the option to log your chats. Not sure if the logs are exportable, but they are searchable.
Most multi-protocol desktop IM clients such as Adium, Pidgin, Trillian, Digsby, etc. keep local logs for all of your accounts, and most have an interface to search those logs. While this works well when you do most of your chatting from one computer, it's not server-based, and is not a perfect solution if you move computers a lot.
Facebook does not keep chat logs, or rather, does not make them available to you, so really the only way to log FB chats is with a 3rd party client.
I recently starting using http://imo.im
It is web-based, multi-protocol chat handler that does video, audio, and text chatting via: MSN, Yahoo, AIM, gTalk, MySpace, Skype, and Facebook.
It save the chat history for all the clients in a easy to use interface.
I have been very happy with Digsby, it archives conversations that could be saved or exported elsewhere.
Try bitlbee if you have a ssh login with an irc client. It enables you to chat with your friends on MSN, ICQ, wherever and hanging around on IRC.
Also, you can use it locally with your graphical IRC client which proves the flexibility of this smart program, allowing you to keep your logs in a single place.