No one likes using a scanner, so that's why we have scanning apps on our iPhones. Most of those let you share PDFs after photographing them to either email, Dropbox, or another sync service. InstaPDF changes all that and syncs them instantly to the cloud and right to your Mac.
InstaPDF lets you use two different modes for scanning documents, an auto-enhance mode or a photo mode that takes a photo of an image just as you see it. For documents, you want to use the auto-enhance. I've always enjoyed the photo mode of PDF scanners for iPhone simply due to the fact that it makes for a convenient way to store things I want to personally reference later.
Where InstaPDF stands out is that it instantly uploads your scans to your InstaPDF account where they magically show up on your Mac and on the web. Yes, you'll have to sign up for an InstaPDF account but it's a very small price to pay for the convenience it provides. I tried both the web interface and the Mac app and they were almost instantaneous. The Mac app simply sits in your task bar and stays out of the way unless you need it for something.
For me, apps like InstaPDF are invaluable since I can easily store documents immediately to share lately. No more leaving things at the office or at home and not having them when you need them. InstaPDF also has an iOS 7 inspired interface so if that's your thing, you'll especially like it.
While InstaPDF for iPhone will run you $2.99 in the App Store, the Mac version is free and can be downloaded from the InstaPDF website via the link below.