iMessage, which in a nutshell is Apple's belated attempt to jump on the free instant-messaging bandwagon (as seen with BlackBerry Messenger et al), may also be integrated to the Mac iChat service, which would certainly add an extra dimension to proceedings.
Mac4ever has posted rumors in a post today where they say that FaceTime, a video chatting service for iPhone 4 and iPod Touch 4G, will soon be coming to iChat which is an IM application that comes with OS X. They also say that iLife 11 (without iDVD) is coming soon.