For information about Star Wars: Revelations, see http://www.panicstruckpro.com/revelations/revelations_movie.html.
Note that downloading these with IE will put it in a temporary folder first, then copy it to the correct directory. This means you will need twice the disk space. Use a better file downloading software if you are having problems with this.
There can be other problems downloading DVD #2 as well since its size is just over a 32bit integer which can cause trouble in some softwares. If you download this file and end up with a file around 2-300MB, your software is buggy. If you're using FAT32, you can't download DVD #2 because FAT32 only supports up to 4GB files and #2 is 4.3GB.
If you want to verify the correctness of your download before you burn, there is a file called MD5SUMS with checksums in MD5 format available. For win32 users, there is a zip-file with the md5sum utility.This mirror provided by Academic Computer Club at Umeå University.