Grant Michaels points to a lovely post on getting started with augmented reality using Flash.

FlarToolkit/Flash Augmented Reality [Mikko Haapoja]

It’s all free for FlarToolkit, and with free tools for Flex out there, you could build a whole free toolchain. Of course, we tend to like Java and Processing round these parts, so I can add “make a tutorial for Java” to my massive to-do list – unless someone else has already done it!