Davide Zordan has another great multi-touch post in which he talks about this approach which is now available in WPF using Expression Blend 4 RC and the TranslateZoomRotateBehavior.
I’ve already blogged about adding multi-touch support to Silverlight applications using Blend behaviors (you can also read my italian language article).
This is a powerful and simple approach which is now available in WPF using Expression Blend 4 RC and the TranslateZoomRotateBehavior.