I have three Pandora Batteries for sale, all brand new. They work with both PSP fat and PSP slim. Pandora Battery is useful if you want to safely install custom firmware to your PSP with no possibility of bricking. The best part is that you can use this battery as many times as you want, so if you have a friend with a PSP, split the cost and it'll be $10 a person.
I will ship internationally, it'll be $21 shipped for Canada and around $25 shipped for everywhere else. If you aren't in Canada or US, please contact me first though so I can give you an exact price.
They go for more on eBay, but I can't risk even getting one item removed because of TOS violations. That's already happened enough and I'll probably lose my account if it happens again.
http://search-completed.ebay.com/search/search.dll?sofocus=so&sbrftog=1&dfsp=32&catref=C6&guest=1&from=R40&satitle=psp+battery+tool&sacat=1249%26catref%3DC6&sargn=-1%26saslc%3D2&sadis=200&fpos=48103&sabfmts=1&saobfmts=insif&fis=2&ftrt=1&ftrv=1&saprclo=&saprchi=&fsop=32&fsoo=2