Answer:
The History of Pandora battery:
http://www.noobz.eu/joomla/news/pandoras-battery.HTML
The Pandora Battery is actually a combination of specially-modified PSP battery, and specially-modified PSP pro duo memory stick.
To make a Pandora Battery, you need a homebrew-capable PSP. This is rather a catch-22 as you need an open PSP to make one! If you don't have a homebrew-capable PSP, you should find a friend who does, or use the information below to find someone who can make a battery for you for free, buy a Pandora battery or buy a Datel Battery Service Mode Tool to convert your battery.
Some scams to beware of:
1. Some people are selling the battery on its own, plus instructions on how to make the memory stick. Making the battery is the easy part, and if your PSP is unable to do that, then you will be unable to make the memory stick.
2. Selling the memory stick may be illegal. If you own a PSP then you are licensed to use the firmware.
3. Many people will try to sell you just the instructions. There are some excellent instructions available for free on the internet, including those linked to above.
4. Many people are simply selling you a link to the website containing the download.
Super newbie guide to making Pandora battery and memorystick: http://forums.maxconsole.net/showthread.php?t=76092
If you prefer to buy one, use your favorite search engine, for example www.Google.com, and in the search field type "buy Pandora battery", you'll have a variety of vendors to choose from.