The stores are all set up basically the same but have different content due to different dates set from each branch/ localization for regions. The Asian stores (Hong Kong, Japan, Taiwan, etc.) are all the same, the UK/ Various Euro stores get the same content and there are two North American stores (USA and Canada).
Anyway, JDubb, what MOM said up above is correct, just go into the PlayStation Store on the PS3 and find the demos you want. Once you do just click the big blue "download now" button with the X on your controller.