Though both OSes aren't supporting all of the hardware yet, the ports are now officially a fact thanks to developers from the XDA forum. Until now the port development was obstructed by problems with the Haret bootloader, which is being used to unload Windows Mobile from its memory and boot Linux afterwards. The developers have progressed alot in that area.

As i said, the Linux ports aren't quite functional yet; support for several parts are missing. Minor things such as wifi and bluetooth are still missing support, but more important features are missing too, such as the touch screen driver. The HTC HD2 being a bar this actually means that you can only talk to the phone through your keyboard, making it that much less mobile.