I believe 8GB is the highest memory stick for the PSP. As for the Pandora Battery, I'm not entirely sure what it does since I've never had to use one, so hopefully someone can fill you in on that. As for where to get the ISO's, I'm sure you know where to get these. If you can find DS roms, then you'll be able to use PSP ISO's. I was getting mine through private torrent sites for a while, but a few months ago I started getting them through newsgroups. It's just faster that way, and there's no seeding. Also, some of the sites that host DS roms also have PSP ISO's