Ok. Sorry it's not working for you. It works for me on iTunes 11, but I'm also using a Mac, so that may not mean much.
You haven't said much about how you're using it, so I'm going to mention a few essentials, just in case they were missed. Expect a lot of redundancy.
The computer must be on and iTunes running. Bot the iPad and computer must be on the same wi-fi network.
To see videos you must use the Videos app. Only music and other audio only content show up in the Music app.
The Shared library must be selected. The videos do not show up inline with what you already have on the iPad. It normally shows up as a gray square with a house in the middle. It can take a while for the library list to load.
Good luck.