TMC Werewolf?

[dataloss]

Silhouettes and Shadow Play are good ways to show things on screen in terms of transformation without having to spend a fortune. Mako's The Hunted used this to great effect.
http://youtu.be/ro0X8wkaIX8

The Close up's and acting style in this video "Mad Dog" that was posted here recently from 3:54 onwards http://youtu.be/GEhs98Bz7NI really pull a viewer into the transformation. It's performance above any make up or cgi that makes or breaks the scene.

Sound Design is very important as Cursebearer stated. Sound can trick your audience into thinking things are happening even when they are off screen. from the squelching stretch of the victims skin as they change and transform to the tearing of clothes. Also music is key throughout and it should build with the scene being both foreboding in the build-up and also giving the transformation a pace and overall feel/mood it would otherwise lack without.