Apple do not repair iPads but will replace one with a refurbished, similar model at a cost of $299.
There are many companies that offer to repair iPad glass. Google for one in your area. This will void yor Apple warranty if you still have one.
Apple warranty only covers manufacturing defects, not accidental damage.
Apple does not do repair, and attempting it yourself will definitely void your warranty.
Rather than googling look in the support area of the Apple site, for a certified service center in your area. They change the glass for about the same price as Apple would exchange your iPad for a refurbished one.
Check here in the Take in For service option for a Service center near you. You can skip most Apple stores if you want to get the glass replaced.
Apple's Limited Warranty http://www.apple.com/legal/warranty/ for iPad excludes coverage for damage resulting from accident, disassembly, unauthorized service and unauthorized modifications.
If you own an iPad that is ineligible for warranty service but is eligible for Out-of-Warranty (OOW) Service, Apple will replace your iPad with an iPad that is new or equivalent to new in both performance and reliability for the Out-of-Warranty Service fee listed below.
iPad model Out-of-Warranty Service Fee iPad mini $219 iPad 3rd, 4th generation $299 iPad 2, iPad $249
A $6.95 shipping fee will be added if service is arranged through Apple and requires shipping. All fees are in US dollars and are subject to local tax.
Certain damage is ineligible for out-of-warranty service, including catastrophic damage, such as the device separating into multiple pieces, and inoperability caused by unauthorized modifications. However, an iPad that has failed due to contact with liquid may be eligible for out-of-warranty service. See http://support.apple.com/kb/index?page=servicefaq&geo=United_States&product=ipad
Make a Genius Bar Reservation
You may can get the iPad repaired at 3rd party repair sources for less $, however, any remaining Apple warranty will be voided.
iPad Repair & Screen Replacement Services
RepairZoom iPad Repair