Generally OS X operating systems have never phoned home or required serial numbers or any sort of system pairing.
its a general rule that its meant for single licensed use.
Now there is no official word on if SL will need a serial, at this point it just needs an installation of Leopard...so I'll go on a limb and say no, no other requirements are necessary.
Also, it probably wouldnt have any negative affect on you to use the same install disc on multiple computers; its just against the EULA.
ive had to use a single disk image of Leopard to restore multiple macs off the same installation and nothing negative happened though they do have their own installation discs , it was just easier to do it off one single image.