Apple just unveiled details of its upcoming OS X 10.8 Mountain Lion, the company OS version that runs on Macbook and desktop. The OS 10.8 maintain Lion is an extension to the previous version that brings many iOS features to the Mac line.
The Mac version of iMessage called Messages adds SMS and unification of all popular chat platforms
The Beta version of OS X 10.8 is available to Mac Developer Program members. But if you already run Lion, you can download the beta version of the new messenger client, Messages