Is it possible to get the iPad to play videos in the common formats? I was looking for an easy to use device for my mum, who wants to occasionally grab movies to watch on the go. I didn't do my homework properly and just bought an iPad because it seems to be a synonym for "easy to use".

Until I found out that to watch movies using the built-in player, they have to be transcoded.

What would you recommend to make it easy for my mum to grab a movie from her computer and watch it on the iPad? Is there an app that would just play any format without transcoding? If not, what's the easiest way out? She's got a pretty slow PC; definitely not something I'd want to do video transcoding on.

P.S. I'm still wondering if I got this wrong, because it's a bit hard to believe. This is anything but easy-to-use at the moment :(  Am I totally misunderstanding something?
I use VLC Player for iPhone, but it was removed from the App Store due to an incompatibility between its open source license and the App Store terms.

I learned that AVPlayer does the same, but it is a payed app. Pretty inexpensive, tough.