I mentioned in my first look of OS X Mountain Lion today that Apple was doing away with its messaging app iChat and replacing it with a new app called Messages.
With Messages you can chat with someone using their Apple ID or phone number, just like you can using iMessage on iOS. You can also use traditional chat services like AIM, Yahoo, Google Talk, and Jabber, so anyone that has your old iChat handle will still be able to contact you using that information.
Here’s the great thing about Messages. It keeps the conversations synced between devices.
Messages beta is available from Apple’s Web site.