The ACME installer requires that you mount the HP Touchpad and then move some files over to the tablet. Once the files are on the Touchpad you can run them. To do this you would have to create a folder called cminstall, copy a zip file over, and then start the ACME installer.
You will also need to get Cyanogen 7 on the tablet and this will let you swap between the WebOS and Android easily. The new OS only needs the ACME installer, Novacom and cm-update payload file. This is not ready for release yet but is so close we can taste it.
As we get more information and the dual-boot files are released for others to test we will let you know. If you have an HP Touchpad, its only a matter of time before you can have it dual booting Android with WebOS.