I am not sure where to get the movies - I am checking and when I find some sources I'll update my answer - but one things you MUST have in order to really be able to see such media on your HTC is good, open WiFi - and not only at home or in the office or your favorite Starbucks, but EVERYWHERE. The best tool for that is WeFi - a small software that you install on the HTC and it automatically scans and finds open hotspots for you, and connects you without needing to lift a finger. It also managers the battery consumption of your internal WiFi so that your HTC will not drain out when you watch a video and then forget to turn WiFi off.
Just go to http://www.wefi.com/app/downloadmobile.html/page/Download to download from your PC (and install through ActiveSync) or from your HTC browse directly to http://www.wefi.com/cab/
I tried it, and I was amazed to find out just how much available WiFi there is around me most of the time - WiFi simply shows you on the "today" screen whenever there is available WiFi around, and you connect by one click. No need to go through a tedious list of WiFi networks and waste time. I watch Youtube on my HTC Touch all the time now...