We need a little more information here.
What model iPad and what version of iOS is it running.
What version of iTunes are you using on your computer?
iOS 6 requires iTunes 10.7 or later and iTunes 11.0.1 is the current version.
Also, just to make sure, when you connect your iPad to your computer you will not see it listed like another device or hard drive. You will see it recognized in iTunes 10.7 or later.
Ad if you are familiar with earlier version of iTunes but have updated to iTunes 11 the interface is different. You can recover the older look by selecting to see the left column in the .view menu of iTunes.
iPad not appearing in iTunes
iOS: Device not recognized in iTunes for Mac OS X
iOS: Device not recognized in iTunes for Windows
IOS: Syncing with iTunes
Apple - Support - iPad - Syncing