Transfering animations to different models

Here is a newbie question:

In Blender can you create an animation for a character and then “apply it” to another character even if it has different size/proportions ? Yes, no ? If yes, how to do that ? If no, which tool would allow me to do that ?

Thanks for your answers,

Yes you can and it is really easy, just select the model with no animation, open the Action Editor and give it the Action you want it to have.