I always forget how to do this:
ffmpeg -i iphone-portrait-orientation.mov -b <bitrate-of-source-file>k iphone-portrait-orientation.avi mencoder -vf rotate=1 -o iphone-landscape-orientation.avi -oac copy -ovc lavc -lavcopts vbitrate=<bitrate-of-source-file> iphone-portrait-orientation.avi
