Whilst I was away a took a number of videos on my camera side on, resulting in side on footage. I didn't realise it but with quick time pro you can actually flip the video really easily.
On an Apple Mac open the film in quick time (this only works in quicktime pro), then choose window, then show film properties (shortcut apple + j). Select the video track then visual settings. There you will find the options for rotating, resizing or flipping the film.
Also I found this really useful page on how to make screenshots in Apple OSX.