Interesting news story in the Register about Sony trying to stop PSP imports
http://www.channelregister.co.uk/2005/06/03/sony_psp_grey_market_fight/
Just shows how important it can be to get your IP registered. It is very hard to control imports and exports of your games/hardware once you have sold them on once (in EU speak its called the exhaustion of rights) but if you have registered marks attaching to these then they can be used for that purpose on occaision.