Some decent progress has been made over the past couple of weeks with getting the HTC HD2 running Google Android. Progress accelerated when a CPU bug was patched that prevented HaRET from loading up. HaRET is needed for booting the Linux-kernel so that Android can be installed.
Just on Thursday the team who got HaRET working also managed to get Android 2.1 and Windows Mobile 6.5 booting side by side.
We now hear that Android for the HTC HD2 is ready for download over at XDA Developers. The thread is quite long, but contains all the details and progress notes that you'll need to get Android or any other Linux based OS installed on to the HTC HD2.
The builds are very early in testing stages which means you shouldn't really bother with installing them if you want to use Android on your HD2 on a day to day basis. Also, make sure you be careful and follow all steps to the letter to avoid bricking your HD2.
What we have heard previously is that so far Android works well with some things although like the iPhone running Android, there's just a little bit too much that isn't right or ready for using as your main phone.
If you install Android on your HD2, let us know how it goes.