Quick answer for how long the iPad lasts: between 10 hours and 30 days.
The apple tablet, unveiled as the iPad, is designed to bridge the gap between the Macbook Pro and the iPhone. Running the same operating system as the iPhone and iPod touch, the apple tablet is said to have a fully charged battery life capable of playing 10 hours of video or 10 hours of application usage. The internal battery will be charged using the same white 30 pin connector cord that charges and syncs other apple products, such as the iPhone and iPod. When resting in standby mode the iPad was said to last up to one month, or 30 days. The consuming public will not be able to verify or test these claims until early second quarter 2010 (the beginning of March).
How long does a fully charged apple tablet iPad battery last? An estimated 10 hours to 1 month depending upon the type of usage.