MakingThings has released an ActionScript 2 library and documentation for their Teleo device sets. This is basically a kit that allows you to control from Flash all sorts of devices, sensors and controllers attached to your computer.
I have been playing around with this, and it is really cool. The library is really simple to use, and makes creating Flash applications that are tied to devices and sensors super simple to create. I will be posting some pictures and maybe video of a couple of projects I have been working on as soon as I get back from Europe.
In the mean time, you can download the library here, and check out the class documentation here. You can also get a Teleo introductory set here.