ieXbeta has found this update to the WMP 9 Series Encoder. Although its in Beta, Windows Media 9 users willing to try this out are able to do so. Heres the info from Microsoft:
Windows Media Encoder 9 Series (beta) is a powerful tool for content producers who want to take advantage of the many innovations in Windows Media 9 Series—including high-quality multichannel sound, high-definition video quality, new support for mixed-mode voice and music content, and more.