I'm in a project were we would like users to interact with a 3D object. Users should be able to zoom, pan and rotate in all dimensions without using extra tools. I'm looking for best-practice design patterns used in other applications today. Examples of 3D applications using multi touch would be appreciated.
Zen Bound (and Zen Bound 2) is an iPad app (usually installed on the Apple Store demo machines) that involves rotating a 3d shape to bind it in a ribbon. You might track it down; it is all about fiddling with a 3d object and its interface was reasonably intuitive.
PS: don't forget zoom. It becomes really important when dealing with complex 3d objects.
PPS: Look into Google Sketchup for more examples of good 3d interaction. It's not touch-based, but their "sticky tools" approach is a major breakthrough: for example, once you start drawing a line, you can switch tools to pan and zoom and generally reposition the camera to your heart's content, and when you resume drawing a line, it is as if you never interrupted the drawing process.
The Google Earth iPhone application does everything you are interested in. Multi-touch interactiong for zooming, rotation, tilt and spin all without the need for a toolbar.