Watch Sabrina the Teenage Witch and many other shows on your iPad for free.
I just found out that Motionempire, a video website, has content compatible with the iPad and iPhone.
You can watch:
Sabrina the Teenage Witch
How I Met Your Mother
Spongebob
Even though Motionempire offers loads of sources, make sure you use Gorillavid, a compatible website with the iPad and the iPhone.