How do I boot the live CD on a Macbook Pro?

Sorted, for all others out there, hold the Alt key down, then wait a while until a CD icon appears, then select in order to boot from CD.

If you press the Alt-key the menu of boot options appear and you will be able to select to boot from CD. On some Macs holding down the C-key will work and directly boot from CD without the hassle of selecting something in a menu.

Some MacBook Pro s (notable MBP 5,1-3) will show just a white underscore instead of booting to the LiveCD's graphical user interface. That is due to nouveau failing on NVidia's 9600MGT. Enabling nouveau.noaccel=1 as a kernel boot option (described here) will fix this. Also pressing F6 during LiveCD boot and selecting nomodset or using save graphics mode with F4 has proofed to work.