Depends on your actual video footage, I suppose. And what version of maya you have, too.

If you have a dynamic camera movement (a lot of movement, say with a lot of pans or something like that), and if you have it, you can use maya live. Check the help files in maya first for the tutorials (maya live may only come with the unlimited version, but it might come with complete). If you don't have that much camera movement (say you're running on a tread mill, and the camera's in place) then what you do is you key the camera that you'll render from to account for that movement (so, from point A to point B over however many seconds).

In either case, if you're going to import the footage into maya, you need to seperate out the video file into individual frames. There are a number of cheap or free programs running around that you can use to do this. Maya should be able to read just about any file format you choose; if you don't have live you just need to set up a camera image plane attached with the 'video file' texture node (it wants indidvidual frames though, not an actual video file). Just make sure all your frames are numbered properly first.

One note here - don't composite the video footage inside of maya - in other words, don't render your animation or whatever in such a way that the video that you shot is visible - use an actual video editing piece of software to composite the two (again, there are a number of means and programs to accomplish that).