I download from the Apple site:
http://www.apple.com/trailers/
Then use TMPGenc with the Apple plugin (from
www.dvdrhelp.com ) to convert to high bitrate MPG2, and play via my htpc.
If you have Zoomplayer, then you can build a trailer playlist that will play random trailers before it plays the DVD, if you don't have that, then you can put a playlist of your software player (PowerDVD for example) in your startup, and they will play everytime the pc starts.
If you can get the DD and DTS vobs, they make a great intro too.
Gary.