As I am the owner of a PSP, by proxy through my son, I'm always looking for ways to tweak the device without actually causing any certain harm to it. Afterall, it's a very expensive "toy" and if I mess it up, my son will never forgive me.
But, after checking out (and somewhat happilly) purchasing the new Media Manager from Sony, I thought, wouldn't it be great if I actually had enough space to store an MPG of 4GB or more on my PSP so that my son could watch an entire movie on it? I went searching around, and found what I was looking to find: a DATEL (MAX) 4GB hard disk and battery for the PSP.
At a steep $200 for the device, it adds some interesting functionality to the PSP that wasn't there before. The addtional bulk that it adds to your PSP will give you longer battery life and the ability to slide microdrives and Compact Flash cards into it. So, you can purchase less expensive versions of memory for your PSP and you'll still be able to use them to store game saves and other cool stuff. You'll need to format the cards on your PC and then drop them into the Datel device, but they'll work great.
Oh, and what about drives LARGER than 4GB? Well, according to my source, anything above 4GB doesn't seem to work nice. At least, a 6GB drive won't. I've seen a post by a user that got a 5GB drive to work. Maybe that's the limit?
At any rate, this add-on makes your PSP a little chunky, but it definitely gives you some good hand grips for holding on while you're watching movies and playing games for those long plane and car trips with the kids!