Understanding Flash Sync, Shutter Curtains And High Speed Sync
Photographer Paul Duncan put together a great instructional video explaining what those darn curtains are, and why they matter for flash photography.
This excellent video, uncomplex some of the more complex concepts of flash photography. It explains the illusive T0.5 and T0.1, the concept of flash and front/back curtain and how high speed sync works (pretty clever).
Kinda makes this whole curtain thing simple as a shower curtain.