Contrast detection vs phase detection for movies?

I'm looking at buying a DSLR camera, and I'm mostly looking at the Nikon D5100 and the Canon EOS 650D (or Canon Rebel T4i in USA). I will mostly be using it for movies, but also for photos as well. I see that the Nikon camera has contrast detection, whereas the Canon camera has phase detection. I have heard that phase detection is better, but I really don't know much about cameras yet.

Could someone please explain the difference between contrast detection and phase detection for movies, and which one would be better, to someone who is an amateur with cameras?

What is not clear in this question is this.

When shooting a script, usually the lens is manually focused in any case, so auto-focus becomes a moot point.

Here is something you may want to read before you spend from $800 to $1, 200 just for a camera that will require you to buy an additional $3, 500 or more in accessories to make it a viable video camera

http://www.luminous-landscape.com/reviews/camcorders/cam-cam.shtml

Contrast focusing is more accurate, but much slower and tends to hunt because it doesn't know which way to focus the lens at first.

Phase is faster than contrast and doesn't hunt as much as contrast because the tricky phase detection system knows which way to focus the lens at first. Phase can have front/back focus (doesn't focus at the point you want) issues which can be corrected in some camera models.

If you're worried about focus for movies, then look to the Sony line of DSLRs. They have Nikon and Canon beat regarding focus technology.

Of course, if you're really serious about video, then get a real video camera. It's a whole lot easier to use than a DSLR. DSLRs are great still camera tools, toys for video unless you get a whole bunch of extra stuff.