well if I understand correctly, you want to import or place a movie or some sort of animated sequence into maya and have it play.

I would create on image plane or a poly plane and size its ratio according to your animated file ( very Important). You should save sequence in frames, using photoshop or after effects. For example if you want second of animation you should have 30 single tiff files, if your maya scene is set to 30 frames per second.

Create a lambert material and add a file texture to the "color" attribute.
When it takes you to the new atts. of the file scroll down to "Use Image Sequence" and click the box. Open the first image file of your sequence on "Image Name". Make sure the files are Tiff's and put Zeros when you number the files, exp. "00001.tiff" For some reason Maya only animates images using the tiff format. Apply the shader to your poly plane and when you play the timeline the sequence should play.

This one way to do it, there are different ways do it. You can do this if you have a TV model in your scene and you want it playing some sort of movie, or like an advertisement for example.

If you want to achieve some sort of 2d cartoon effect like in South park, just work on your orthographic view and lock the camera to your plane, make sure the camera is set to orthographic view.