Also I was wondering something about the PS3. How can you backup the HD? To an external USB one?
Yep, but only FAT32 is supported, so keep it low. It won't let you backup everything, and you can't use the files on another PS3.

A good idea is to make 2 user accounts, and fake one in the US. You must have a valid zipcode and you give any information you want like:

Paul Smith
Acacia avenue, 712
Palm Springs
FL, 30847 (only an example, don't try it)

Now with that account, you can enter the US download section, which is a lot bigger than the one in the EU. Like that you can d/l every demo you want and are not restricted to the EU only demos. Try it out, the PSN shop is also slighly different.

They have a demo of the new Ratchet & Clank game which is very impressive, we don't have it yet.