Here's a little of what she has to say, plus a bit of info from my own checking it out. (To go to Maryann's blog, click here.)
You get QR codes from TinyURL. When you go to TinyURL, if you click on the help button in the upper right, it will take you to a page that explains what they are (sort of) and how you can use them (sort of). Here's what it says:
QR CodesQR Codes (mobile barcodes) are links that a mobile phone can recognize and automatically click on. Any regular URL can be changed into a mobile URL. To generate a QR Code from a newly made Tiny URL - click Get QR on home page (Recent URLs) or alternately, append /qr to any previously made tiny.cc URL. Tiny QR Codes are dynamic, meaning you can change the QR landing page anytime after the QR Code has been printed or distributed simply by editing of the destination URL from your tiny.cc account. For example generate qr codes for business cards.
• Manage all of your QR's right in your tiny.cc account and tell at a glance which URLs are being used in QR Codes. Click Note tab and check box next to "Mark this URL as a QR Code", then click Update Note. This puts a QR icon in your link list - making it a snap to identify the QR Code URLs in your account.
• Our default QR is 150px. Need a larger one? Click the "Print QR" button to get 500px. It will print out at 500 px or you can also cancel the print and Save Image As...
• Tiny's QR app finding tool instantly locates software for your mobile phone. It checks nearly 1,500 models! and compatibility with nine of the best QR scanning apps that are available free of charge.
Next to 'Help' is 'Example.' If you check that, you'll be taken to a screen that will let you download your own QR Codes for your books, once you've signed up and registered for TinyURL. It looks like this:
Use Tiny to track QR Code campaignsTiny can provide tracking stats and also generate free QR codes. How our QR-Codes work
I haven't tried it yet myself, but according to what I read, it's easy-peasy. It looks like an upgrade to older, clunkier systems. The only drawback is that your customers have to have a smartphone to go there and buy your book.