Yes, there are plenty iPad apps that allow you to watch TV programmes on your iPad.
You can watch TV by using Netflix or Hulu Plus apps, but they are not free as you have to pay subscription fee. The good news that there are plenty free apps:

• ABC Player by ABC Digital
• NBC by NBC Universal, Inc.
• TV.com by CBS Interactive
• WSJ Live by Dow Jones & Company, Inc.
• PBS for iPad by PBS
• TBS for iPad by TBS
• XFINITY TV by Comcast Interactive Media
• Crackle - Movies & TV by Crackle, Inc.
• TNT for iPad by TNT
• TWC TV by Time Warner Cable
• CNN App for iPad by CNN Interactive Group, Inc.
• Optimum for iPad by CSC Holdings, LLC.
• HBO GO by Home Box Office, Inc.
• Showtime by Showtime Networks Inc.

If you live in the UK, some of the TV programmes from the above apps may not available to you as they check IP address. You can download free apps that provide programmes in the UK such as iTV player, BBC iPlayer, 4oD Catch up, etc.