Introduction
MAC OSX Lion Mountain, a new operating system from Apple which is coming in summer 2012. It will has many of the iOS system features that we already know with iPod, iPhone,iPad. One of these new features that was introduced with iOS 5.0 is iMessage. Now, as a Beta version, iMessage can be installed on MAC OSX Lion. In this article, I will be showing you how to install Messages, which will give you the ability to send unlimited iMessages — including photos, attachments, and more to iPad, iPhone, iPod touch, and Mac. From your Mac.
Here are the features you can expect with Messages:
- Send unlimited iMessages to any Mac, iPad, iPhone, or iPod touch.
- Start an iMessage conversation on your Mac and continue it on your iPad, iPhone, or iPod touch.
- Send photos, videos, attachments, contacts, locations, and more.
- Launch a FaceTime video call and bring the conversation face-to-face.
To download iMessage Beta for OSX Lion, go to : http://www.apple.com/macosx/mountain-lion/messages-beta/
and click on the Download Messages Free Beta button 
The download will start, once its is completed, double click on the MessagesBeta.dmg file to open the package
Then double click on the MessagesBeta.pkg package file
The Welcome to the Message Beta page will open, click on Continue
Read the Important Information page and then click on Continue
Accept the Software License Agreement by clicking the Continue button
Select where to install the package, click on Install and enter an administrative username/password when asked.
Messages installation will be completed. You will need to restart your MAC in order to allow changes to take effect.
Messages icon will be automatically added to the Dock, click on it to run Messages
The Welcome to Messages page will open, click Continue
Sign in with your Apple ID account and then click Sign in. If you don’t have an Apple ID, then you will need to create Apple ID in order to sign in.
After you sign in with your Apple ID, you can add other email address which messages can be sent to as well.
Messages can be connected to other Instant Messaging clients, such as AIM, Yahoo Messenger, Jabber, Google Talk.
If you want to skip this option, then simply click the Continue button.
Once done configuring Messages, click on Done.
Click the pencil icon to start typing a new message , type the name, email address or the telephone number of the person you want to chat with, and then start typing your message.
Note : I have my contacts saved inside the Address Book application.