I found this code from this thread http://forum.unity3d.com/threads/49306-Camera-placement-size-behavior. attach the script to a camera game object. put directly over the terrain. But the problem is the camera view is on the right side of the screen and its square lol. I want to move it to left and change the view shape circle. Thanks In Advance 
447996–15575–$MinimapCamera.js (267 Bytes)
You couldn’t do that with the camera alone. You should use render targets. I hope this would help.
explain. do you mean render textures?
Yeah, render texture / render target would help.
THANK YOU! would never had thought of render texture. 
Still can’t make it circular shape and it looks transparent. 
Render texture is capable for doing post process effects, and you could do whatever effect you want to make. Maybe you need to get a circular mask to achieve such effect and create a shader that would filter the circular mask over the rendered texture. something like that.
Going to try it. But to let everyone know found a site to help people make a mini-map http://www.moddb.com/games/caredu/tutorials/how-to-make-a-minimap