I cracked the front glass on an iPad3. When I replaced the glass I accidentally cut the antenna while removing the broken glass. So I had to fix both.
I used a heat gun to carefully remove the glass, removed the screen and dock connector, swapped the antenna and reassembled, all in about 30 minutes.
Be careful when removing the front glass from an iPad3, it is easy to mess up the antenna (right side of home button) during the process. Use the iSesamo!