Get SnapShot

Hello Everybody,

I am a beginner and developing an application where I need to take a snapshot of the openGL window and convert it into a png image. Can anybody please guide me for the same.

Regards,
Paras.

An opensource software: http://getgreenshot.org/
Manual: http://eonstrife.wordpress.com/2007/06/02/taking-a-screenshot-from-an-opengl-application/