Corel announced today that WinDVD 8 has been approved by Dolby Laboratories for Dolby TrueHD and Dolby Digital Plus playback. Here's part of their press release:
Corel Corporation, a leading developer of graphics, productivity and digital media software, today announced that Dolby Laboratories, Inc. has approved its InterVideo WinDVD 8 HD DVD/Blu-ray software for Dolby TrueHD and Dolby Digital Plus playback.

Dolby TrueHD unlocks the ultimate high-definition audio experience, delivering studio-master-quality sound from HD DVD and Blu-ray Disc formats, while Dolby Digital Plus delivers up to 7.1 channels of dramatic surround sound for HD DVD and Blu-ray Disc players and home theater systems.
If you'd like to read more, Corel's entire press release can be found here.