I tried to install 12.04 (32 Bit) on my 2009 MBP from CD. Partitioning, setting the timezone and entering the user name and password for the first user worked just fine, but just a few seconds after that the install failed several times with a read error from the CD.
I tried another CD, but with the same results, so I think it's neither the CD nor the drive.
Then I tried to boot from a flash drive as described on here, but it didn't even show up in the list of available boot volumes.
Pretty unsatisfactory. I've used several flavours of Ubuntu since 6.06 on several PCs, even an old Sparc workstation, and none of them gave me nearly as much trouble as any piece of Apple hardware I've tried.