A coworker has a white MacBook - he is unsure as to when he bought it, but he said it's still running Leopard. As he bought an iPhone 5, he needs Snow Leopard. Will a retail version of SL be enough for the upgrade?
Unfortunately, that's not enough information for anyone here to be of any help. Get a screen shot of his 'About This Mac' screen (Apple -> About This Mac -> More Info...), or anything regarding the specs of the machine, and someone should be able to help you determine if it can run Snow Leopard.
To find out, what exact Mac model you use, click > About This Mac > More Info > Hardware Overview:
To see a more elaborate image explaining the above steps, click here.
To see a more detailed video tutorial showing the above steps, click here (2 MB, 23s, .mp4).