Howto install VirtualBox 2.0.2 Guest Additions in Ubuntu 8.04 and 8.10

EDIT: I noticed a lot of people using the newly Ubuntu 8.10 are visiting this page to get their VirtualBox working properly. These instructions should still work.

If you use VirtualBox you probably are very curious to use the Guest additions, because they make it possible to have seamless windows, auto-resize screen, mouse pointer integration, better display drivers ... If your guest OS is Ubuntu, you probably had some trouble with installing them. Normally you only need to go to devices and press 'Install Guest Additions' (when the OS is up an running) and it should get installed without problems.

Now with Ubuntu it doesn't work like that. A cdrom get's attached, but it doesn't run automatic. So first I will explain it for Ubuntu 8.04 how to run it.
1. Open a terminal (goto 2 if you know your own way)
1.1. Press Alt-F2
1.2. Type 'gnome-terminal' and hit enter
2. Type 'cd /media/cdrom/' and hit enter
3. Type 'sudo ./VBoxLinuxAdditions-x86.run'
4. Now you need to type your password (the install needs root-rights)
5. Like the message says, afterwards you need to restart the computer to let the changes take effect

For Ubuntu 8.10 beta 1 it is almost the same. But first you need to be sure you're working with VirtualBox 2.0.2. Prior versions will not work with Ubuntu 8.10. If you got that you need to do the same as above. After the restart you will still need to do some things, because the screen driver isn't activated by default.

1. Open a terminal (look above if you don't know how)
2. Type 'sudo gedit /etc/X11/xorg.conf'
3. Type your password (needs root-rights again and afterwards a text editor should appear )
3. Find:

Section "Device"
 Identifier "Configured Video Device"
EndSection

4. Change to:

Section "Device"
 Identifier "Configured Video Device"
 Driver  "vboxvideo"
EndSection

5. Save (press ctrl+s)
6. log out and log back in (restarting also works)