^^ not technically true (regarding headaches and dvd's)
The Tridef drivers can convert dvd quality footage into 3d from a 2d source based on algorithms calculating shadow, movement, position etc. in a scene which actually works rather well.
For the tridef drivers you need to be running either a 120hz screen, or a Zalman Trimon 3d monitor like the one I'm getting (it's the first 1080p 22" 3d monitor) which uses polarisation rather than shutters, so no headaches, no expensive glasses (although cheap glasses are still necessary) and means you can watch a film with more than one person without having to shell out a hundred every time an extra person is added to your party.