CyanogenMod for the HP Touchpad has been released after a two months of hard work from the developers behind the port.
This is in ALPHA stage which means it is no way ready for everyday use and still has a huge amount of bugs and problems.
You can head over to the discussion thread on the topic and download a copy for yourself. The thread also states nearly every little bit of detail on the ROM and has a list of what is working and what isn't.
There a number of complicated steps so it's recommended only advanced Android users try it.