Flixster has launched a new Roku channel for viewing movie trailers, and it supports HD! To install the new Flixter channel just visit the Roku Channel store -- it should be available to everyone now.
The trailer selection screen uses the standard Roku user interface:
I'm a big fan of movie trailers, and since the Netflix channel doesn't offer trailers, I'll be checking out the trailers on the Flixster channel.
Reader Noor has posted a video tour of the new Flixter channel on YouTube.