It is realy simple and can be shown easy.
If you don't care about quality you click the first link.
http://movies.apple.com/movies/wb/sh...tlr1_h.640.mov
Stay on SD and sell your PC monitor you don't need it a SDTV CRT will do fine via S-video out.
If you care about quality you click this second link and upgrade your equipment.
http://movies.apple.com/movies/wb/sh...lr1_h1080p.mov welcome to HD
I click the second link. I no longer ever click the any thing below 1080p on trailers any more.