What do I need to do to convert a DivX/xVid/whatever-format movie into something

[Joe]

playable in iTunes/Apple TV? I have an older (hacked) Apple TV that I'd like to convert to use more "practically". While this doesn't mean I'm going to "un-hack" (reset) it or anything, my friends and roommates find it slightly too confusing to navigate, and as such, I'd like some of my movies to be playable through the default Apple TV software.

As I understand, what I need to do is convert the files to be readable by iTunes, correct? Okay, then, first things first: What do I need to do, in order to convert some of these files into a format that can be read by iTunes (or whatever it is the old Apple TVs use)?

Next questions, then:
- Will the files be significantly larger than the DivX/xVid files that I currently have?
- Will the files have thumbnails similar to others that are downloaded through iTunes onto the Apple TV?

- Will the sound or picture quality be worse at all?

On a related note, are there ways that I can convert an entire DVD (menus, special features, subtitles, and all) into a digital file format that can be read by my Apple TV?

[Arwel]

You need a video converter

heres a link to download a free software that will work
http://www.videora.com/en-us/Converter/iPod/

and heres a link to the one I use which you have to buy but is very good
http://www.cucusoft.com/