I have the following image:

The gray version of the pin will obviously be it's shadow. I know how to skew it and all to make it look like a shadow.
What I want to do but don't know how is to blur the shadow version of the pin more a the top and less as you go towards the tip of the pin shadow.
I want to do that because in real life, the shadow will be more softer as it gets farther from the object that casts it (as can be seen in the bellow example).

Thank you!
UPDATE:
Just to clarify: I need a map style shadow, not a simple drop shadow. Something like this:




