I wish this was available for macs.
I found out after I purchased a few Apress computer books, that I can get the PDF versions of the same books for $10 each. Normally I wouldn't have thought twice about it and dismissed the idea, but Foxit reader is completely free and way faster than Adobe's reader so I decided to check it out. I found out you can highlight text on it! If you're interested in using that option because you don't want to mark up an actual book in which you can't reverse, you'll love this option.
I bought the digital books, and now I'm able to scan through quickly to remind myself of the important points. Priceless as this saves tuns of time. You can also add notes -and those are just two options out of the many this program has.