I heard that when u purchase Lion you can install it on 5 computers. How can I find out how many authorizations i have left?
The Lion upgrade can be installed on all your authorized personal Macs.
no
you have to buy it to install it on another mac
Lion EULA said:2. Permitted License Uses and Restrictions.
A. Standard and Preinstalled Apple Software License. Subject to the terms and conditions of this License, unless you obtained the Apple Software from the Mac App Store or under a volume license, maintenance or other written agreement from Apple, you are granted a limited, non-exclusive license to install, use and run one (1) copy of the Apple Software on a single Apple-branded computer at any one time. For example, these standard single-copy license terms apply to you if you obtained the Apple Software preinstalled on Apple-branded hardware.
That only works for iLife.To be honest, if you authorise your wife's mac using your mac app store login credentials, then you should be able to update it for free as one of your 5 personal computers.
Check how many authorisations you have left - iTunes -> iTunes home -> Sign in -> Account (under Quick Links) -> You'll see "Apple ID Summary", it's under there... "Computer Authorisations: You have x number of computers authorised to play content with this Apple ID"