Installing ubuntu 9.10 (Karmic Koala) on a Mac Book Pro 5,5

First (can't say it often enough): BACKUP ALL YOUR DATA. While you can use e.g. the free version of Superduper! to keep a bootable clone copy of your system on an external harddrive partition, you have TimeMachine as a very convenient program to keep your data backuped, so there is NO EXCUSE for you to not have backups, just in case you accidentally crash your system.

Installing ubuntu runs without problems, as long as you keep some small things in mind.
Adjust the partitions to your needs, as has been posted e.g. here

My MacBookPro was a little tedious about booting from CD having already installed rEFIt (which you should do before the whole procedure - have a look at e.g. this blog post). I had to press the option key during startup and boot into rEFIt and restart the computer from there pressing the option key again, until after two or three trials, the CD finally showed up. Probably due to slowness of the optical drive...

Remember, as has been pointed out here in the dual boot section, that the boot loader needs to be installed into the linux partition. You can tune the grub installation by clicking "Advanced" in the 7th step of the installation guide.

After a reboot ubuntu started without any problems, but of course some things were broken (obvious things like graphics, wireless lan, backlight control, sound).
The following section was written after trying all the tips of this page (thanks and credits to all the authors there!) - all of the following was stolen from there.

Mac-specific Repo

First I added the mactel repo by commanding

sudo add-apt-repository ppa:mactel-support

Then by

sudo apt-get update

I updated the whole distro. Don't forget to reboot afterwards before you do anything else.

After that I installed nvidia-bl-dkms and pommed (responsible for LED dimming support, keyboard backlight control and function keys) via

sudo apt-get install nvidia-bl-dkms pommed

To operate, nvidia-bl-dkms must be in /etc/modules file to load. Open the file in an editor with:

gksudo gedit /etc/modules

and add to the end this line:

nvidia_bl shift=2

The shift option reduces the dimming range to make it more comfortable. You can tune the value as you want.

Graphics:

Go to System -> Administration -> Hardware Drivers and choose the nvidia 185 driver from there to install. After a reboot you should have nice graphics and desktop effects.

Wireless:

Since the install over System -> Administration -> Hardware Drivers is supposed to be problematic, I chose the direct version over the terminal via

sudo apt-get install bcmwl-kernel-source

Having done so a reboot brings up the airport card perfectly configurable.

Sound:

worked perfectly after casting

sudo apt-get install linux-backports-modules-alsa-karmic-generic
sudo apt-get install gnome-alsamixer

rebooting and then unmuting all necessary stuff via gnome-alsamixer.

Sensors:

Edit /etc/modules:

gksudo gedit /etc/modules

and add to the end:

coretemp

Touchpad:

Runs out of the box. You can enable two-finger scrolling by editing System -> Preferences -> Mouse (Tab Touchpad).


So far so great. As a side note, I really like apt-get in comparison to OpenSuSE's software management YaST, it is much faster and easier to handle. Testing and fine tuning of e.g. the keyboard backlight, function keys and so on will follow.