Moving files from an older G4 to a slightly faster one, etc.

I have read numerous methods of transferring files though haven't had an opportunity to try any. My main issue is I want to move only certain files and applications, not the OS. The newer on has Leopard and I want to keep it, but iTunes, iPhoto, etc. I want from the other. Is this possible without the need to reinstall everything. Also, I do not have the Leopard installation disks. Will the latter find updates especially to the OS?