maya said:
If I remember correctly from previous version and nothing has changed in this regard with the latest version of QT then you have to export the movie and its a effect that you make the movie into Black and White.
Yep. In QT Pro 7, here's the recipe:
Open the movie and move the slider thingy to a nice representative frame (this will help when you get to the export options).
Pick Export.... from the File menu, and click on the Options... button to the right of the Export: menu in the dialog that pops up.
You now have a Movie settings dialog. Click on the Filter... button up in the Video section.
Click on the Adjustments triangle and then on the HSL Balance item that appears. There, you can slide the saturation down to zero.