I mainly followed the iBoot + MultiBeast: Install Mac OS X on any Intel-based PC tutorial.

• I upgraded the BIOS of the P7P55D-E board to the latest version 1504. This is because I wanted to try the “UserDSDT” Installation method in MultiBeast, and a DSDT exists for this version. Not that I have any idea what exactly the difference is between the “UserDSDT” and “EasyBeast” modes of MultiBeast; Sleep mode was supposed to work with UserDSDT, so I went with that.
• I reduced the installed RAM to a max of 4GB, as instructed. I cannot confirm whether this is really required or not.
• In the BIOS, I switched from IDE to AHCI under “Configure SATA”, as instructed. Indeed, MacOS X refuses to boot without it.
• I followed the normal iBoot/MultiBeast install process. I also had to use the PCIRootUID=1 flag; the initial boot of the installation CD took quite a long time; using the -v boot option, it appeared to hang at “Bug: launchctl.c ….”, and “systemShutdown false” for a while, but ultimately moved on after some minutes.
• After the installation, I applied to 10.6.7 combo update, also as des cribed, and then ran MultiBeast, using the UserDSDT method, and making sure to apply the PCIRootUID fix permanently.
• After a reboot, Ethernet no longer worked (even though it worked fine after the install; and it also worked fine in my tests using the EasyBeast method). The problem seems to only occu r with UserDSDT. What worked for me was installing the Lnx2Mac Realtek RTL81xx Driver (even though the 8112 chipset on the board is not listed as supported). The driver can be downloaded manually at the link given, I used the version included in MultiBeast.
• The graphics didn’t work properly. This is because current versions of Snow Leopard do not include a driver for ATI 6000 series cards; the key seems to be kernel extension named ATI6000Controller.kext. The file is specifically only included in Snow Leopard versions and updates intended for the 2011 Macbook Pro. Those files can be ripped from the Macbook Pro install CDs. This is discussed extensively in this thread, with instructions and downloads. Someone also posted a self-installable package, which I used and which worked well.
• I subsequently installed Ubuntu on the same disk, and was unsure whether to have it install Grub on the main disk (overwriting Chameleon), or just in the Ubuntu partition. I can confirm that the former works just fine – Grub seems to be able to boot into MacOS X without any trouble.