In Game Animation

http://www.youtube.com/watch?v=gaKDttsEwCs

There's a 1 and a half minute video which shows how to very quickly make an animation using Unity's built in editor. If you have a bit of experience with keyframe animating then you will instantly understand it.

Then use Blender or Something for Animation and Then import the required animation in unity or Go For unity4 it is having Mecanim animation system inbuilt.....And use Animation.Play which able to play the animation as well as stop any other animation applied to the same.....For more info refer -------> go to help unity scriptreference....to Animation.play();

link text this link for Syntax reference Enjoy

   Hope this will work for you......