Apple Online StoreIf your iPad requires service due to the battery’s diminished ability to hold an electrical charge, Apple will replace your iPad for a service fee.

Note: Your iPad is not eligible for Battery Replacement Service if the product has been damaged, for example, as result of an accident, liquid contact, disassembly, unauthorized service or unauthorized modifications, or if the product is not operating correctly as a result of a component failure. Please review Apple’s Repair Terms and Conditions for further details.

The service costs US$99, plus $6.95 shipping. The total cost is $105.95 per unit.

Battery replacement service may be arranged via your local Apple Retail Store or Apple Authorized Service Provider, or you can contact Apple Technical Support.

The data on your iPad will not be preserved since you will receive a replacement iPad that will not contain any of your personal data. Before you submit your iPad for service, simply sync your iPad with iTunes to back up your contacts, calendars, email account settings, bookmarks, apps, etc.

If you arrange service by calling Apple Technical Support, you can expect service to be completed within approximately one week from the time you send your iPad to Apple.

More info here.