Embed Google Maps like in WordPress.com

Hej,

I want to let my users embed google maps the same way as done in wordpress.com
that means:
Translate google maps iframe to shortcode.
And Render Shortcode to Iframe.

I guess this plugin is a good start:

http://wordpress.org/extend/plugins/unofficial-wordpresscom-google-maps-shortcode/

But its not a full solution.

Anyone?