Are you ready? Very simple guide, won’t take long:
iTunes – Yes (of course it does!)
Curzon on Demand – Yes
Blinkbox – Yes (iOS AirPlay mirroring only at present)
Netflix – Yes (also native app on Apple TV)
LOVEFilM – No (deliberately disabled)
Now TV – No (deliberately disabled)
In all cases, assuming you have a Mac laptop or desktop, you should still be able to stream movies to your Apple TV using OS X Mountain Lion’s built-in AirPlay support through all of the above services web sites.
Be aware that reasonable playback performance is not guaranteed using this method (LOVEFiLM Instant HD was particularly bad).