I made one a while ago tutorial in which we explain how to install Android on the iPhone 2G with the help of an application called iPhoDroid, for Mac specially made to automatically install all the files necessary to run Android on the iPhone 2G. Well iPhoDroid has now been updated and works with both iPhone 3G and iPhone 2G, so if you have a Mac around or one installed in VMWare then you can use this application to install Android on your terminal.
Unfortunately, there are no details regarding the availability of an Android version for iPhone 3GS, however, a version for iPod Touch will be available soon, so if you have an iPod Touch you will be able to test Android on your terminal.
You can find the tutorial for installing Android on iPhone 2G/3G using iPhoDroid here and the application for Mac OSX can be found here. Careful! The application is still in the beta version, so it is possible that it will not work properly!
