http://www.smh.com.au/news/breaking/first-highdef-dvd-films-released/2006/04/19/1145344128511.html not much cop for the first releases like Phantom of the friggin opera
There are a few available from your local torrent stockist. Search for 720p or just list the film torrents by size as the HD stuff is usally the biggest. I'm DLing lost in HD but I don't know how good the actual quality is yet. Have you got a HD screen hooked up to your pc?
How are you hooking up to your plasma? I've got a dvi - hdmi cable. The quality is way better than using an analogue cable.