My MacBook Pro came with OS X Mountain Lion, does this mean I can load it on 4 other Mac's? If so how do I do that?
No, the copy that was pre-installed is only licensed for that one Mac and won't appear in the Purchased tab of the App Store. If you want 10.8 for other Macs you own, you'll have to purchase it through the store on another Mac.
You would need to purchase Mountain Lion "once" from the App Store on one of the other Macs, and then you could download it again and again for all your other Macs at no additional charge.
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