Source: http://gematsu.com/2011/09/playstation-vita-will-offer-external-battery-option

PlayStation Vita has 3 to 5 hours of battery life when fully charged. For some, that’s just not enough. Luckily, Sony is preparing an external battery that will extend the life of your handheld. 

“We just announced the peripherals for PS Vita, as well,” Sony Worldwide Studios president Shuehi Yoshida told IGN. And one of the peripherals is the external battery that extends the battery life on PS Vita, that you can connect to PS Vita.

“So if you’re flying from New York to San Francisco, or vice-versa, you’ll have no concerns if you have an additional, external battery.”

I will likely buy it.

great news. i'm still waiting for a remodel

Good news, I might pick this up. Given I am all over the place about my purchase of the Vita.

Hopefully if will be decently priced

Wouldn't it be hilarious if the battery add on looked as ugly as the 3DS nub cradle?

It would be hilarous but it won't happen - you need clear unobstructed acess to rear touchpad which means that charger will probably have traditional 5V input in the sides (or be a usb charger).

Yeah.  It'll probably just be a little protrusion on the botto, or something.  Quite smart, actually.  A little battery that sticks on top of the 3DS or runs down the back would go a long way to silence critics, too.  Quick and easy to stick on and remove, too. Just plug it into the AC adapter port when you need it.

Well good for users but not for company.

With normal input everyone can make knock offs from such design and Nintendo cradle can be protected by IP laws to farm more money from licenses.

Good news..will add to the official thread ;) thanks