Let me introduce u all the next generation of web application – The Web Base Messenger System. This website allow you to connect to Yahoo IM, MSN, AIM or ICQ, Jabber or GTalk. The interface design looks great! Although this website is still under alpha release, it works fine! Everything run in one page. Yes, you are right they r using AJAX (Asynchronous Javascript And XML).

This service will be very useful when you are using a public computer where there is no Instant Messenger installed (ex: Yahoo, MSN, etc).

Check out their site at Meebo