UPDATED with one-page files for home printers
Directions:
All you have to do is print one of the pre-addressed postcards below, put a stamp on it, and mail it. If you can’t find your embassy among the pre-addressed postcards below then print a blank postcard and check this link for a complete list of embassies. This postcard has been designed to be sent to Iranian diplomats and officials around the world from people all over the world. Let them know that it is not too late to be on the side of freedom and democracy. 
GIF: Back of postcard for web use
NO ADDRESS 
AUSTRIA: Iran Embassy 
BELGIUM: Iran Embassy 
CANADA: Iran Embassy 
FRANCE: Iran Embassy 
GERMANY: Iran Consulate GERMANY: Iran Embassy 
NETHERLANDS: Iran Embassy 
NORWAY: Iran Embassy 
SWEDEN: Iran Embassy 
UK: Iran Embassy 
USA: Iran Interests Section This postcard has been designed to be sent to Iranian diplomats and officials around the world. Let them know that it is not too late to be on the side of freedom and democracy. A list of embassies can be found at this link This postcard has been designed to be sent to Iranian diplomats and officials around the world. Let them know that it is not too late to be on the side of freedom and democracy. A list of embassies can be found at this link