Update 20131002: I have been happy now for some time running Android on the HP Touchpad. Still running the old CyanigenMod7 which just crashed and reinstalled following the steps below.
Just follow instructions from cyanogenmod touchpad port team, Download section. Be sure you install everything including ClockworkMod.
Then install GoogleApps so you get Market application:
- Boot into Android mode
- Connect TouchPad to Computer
- Touch the notification icon so you are able to turn on USB
- From the computer drop the GoogleApps zip file (for example gapps-gb-20110828-signed.zip) into the TouchPad
- Reboot the TouchPad (Power + Home buttons for 15-20sec will do it in case just Power does not give you the reboot option)
- In the boot menu quickly move using the volume keys to option "ClockworkMod". Press Home button to accept
- choose "install zip from sdcard", then "choose zip from sdcard" and pick the GoogleApps zip file.