-I have a 720p tv and dvd palyer with hdmi output. I also have 720p movies. I want to burn them because they are too large. They are 6-12 GB. How can i cut them and burn the pieces to 2-3 DVDs?
-The subtitles are the same with normal-format movies? If i download subtitles for the same movie(in normal format) will also work for the HD movie?
Thank you.

Well, I don't know much about any of this. What format are these movies in on the computer? I don't know if you can burn 720p movies to regular DVDs. maybe check Nero for HD support?

Regular DVDs are 720x480, but that's interlaced, so I think you have to have HD DVD or blue-ray to have true 720p support.