SP2 boot disc

During this past september, ASUS & kadavil, gave me some tips on how to slipstream SP2 with downloads avail here at MG. check out thread winXP-sp2 Boot Disc.
I've continued reading and now have a different question re the boot disc issue.
My 2 machines both operate Win XP-SP2. The primary machine has an older version 2002, w/o SP2 on the disc. My laptop has a much newer version and the disc includes SP2.
I've been reading about the use of the "sysprep utility" and how this is usefull for networked boxes. The article goes on to say that this tool can remove the security identification info for the master computer as well as the computer name and you end up with a virgin copy of XP-SP2 that can be used with a disc imaging program to make a new disc for use on other computers in your network. The info continues into explaining how to use setup manager for effortless unattended installation.
If this info is correct doesn't this method avoid the need to purchase a copy of XP W/SP2, for other machines, networked or not.
Does this mean that I can follow the instructions and essentially use my second copy of XP w/SP2 instead of going thru the slipstream method, and make a boot disc. This sounds too good to be true and I'm leary of the method.
any comments before I start, by-the-way...any Rx's on an imaging program that's free.
many thx...dandla