If I buy a Mac that comes with Lion, can I install it on my old Macs too? [duplicate]
Possible Duplicate:
Does buying a new mac also get you Lion on your Apple ID?
If I buy a new Mac with OS X Lion, will I then be able to update my old computers to Lion via the Mac App Store without charge?
No - macs ship with one license to Lion - for that mac.
If you buy an upgrade outright, that applies to all your macs.