If you are like me, you have dozens of video clips from digital "still" cameras which are rotated 90°. And like me, you find them hard to watch in their original form. Luckily, this is easy to fix with QuickTime Pro.
Open a .mov or .avi file from your camera using the QuickTime Player which you have upgraded to Pro:
Under the Window menu is a Show Window Properties item. A dialog pops up and you should see a list of tracks. Choose the Video Track, and then click on the Visual Settings tab.
Click on one of the circular arrows. Your movie will rotate 90° and you can now save it in a form suitable for friends and family.
I don't know why iPhoto doesn't do this. It should.