I know that you can't use your MB restore disks to reinstall Tiger on the MBP, but I'm not so sure that the iLife has locks on it. Having said that, if you were to remove iLife '08 from the MB (and as a result, you still have the license, but you're not using it on multiple machines), you
might be able to use
pacifist to extract iLife for use on the MBP.