Well - we all know you can rip and put films on your PSP, how about this - you can now get a 4GB hard drive for them! Yup, it sits on the back of the battery pack (Well replaces it!)
The X2 Battery is a direct replacement for your PSP's rechargeable battery, but offers double the capacity of the standard model. Now bundled with a 4GB HDD, it gives you plenty of space for your saves and files on the go.
Coming it at a cool $249 @
http://www.lik-sang.com/info.php?products_id=7825
This now allows you to have more than the poor 32MB card which Sony ship in the Value Packs