The Prius is the world's easiest car to jump using the jumper terminals under the hood but be very sure to get the polarity right. It takes 30 amps for a second or so and that's only to run the brake pump, other than that it only has to power up the electronics and throw a relay (the Prius has no starter motor). Most jumping kits are way overkill. Purchase the smallest one available. I have yet to need a jump start on either my 2001 or 2004 Prius.
The power port is not connected when the Prius is off so you can only charge devices when the Prius is in READY mode. Also the wiring to the power ports is quite thin, so you don't want to run very much off them them.
Take a look at priuschat.com or one of the Yahoo Prius groups for more information on running emergency power from the Prius.
http://priups.com/ also has some good information on emergency power from the Prius.
About Prius Battery jump start and recharging from cigarette lighter?
Linear Mode
