Good Gear Guide
In Pictures: A sneak peek at Apple's upcoming OS X...
Goodbye iChat, hello Messages
If you're an iChat user, fear not; this isn't a wholescale rip-and-replace of your IM client. All the iChat features remain, but the app has been renamed Messages, and it integrates with the iOS iMessage communication system, meaning you can send text or images to anyone on an iMessage-capable iOS device or Mac, including multiperson chats. The iMessage system transfers data via the Internet, so there are no text charges if you're sending messages from or receiving them on a mobile device.
In Pictures: A sneak peek at Apple's upcoming OS X Mountain Lion