I just uploaded the latest version of ArtoolkitPlus to Frementle devel, so you can start playing around with it soon. Artoolkit is a marker tracking library which allows Augmented Reality applications similar to ARhrrr possible. I am currently working on a AR application for the N900 as part of a project work for the university. Of course it is not quite as advanced as ARhrrr, but it certainly runs better than this demo on the iPhone 🙂