QR Barcode image back to text

I use the ZBar bar code reader on linux (there's also a Windows and an iPhone binary), which can scan them using any supported video in device or a number of file formats (e.g., directly from PDF). It's also useful if you want to script the QR code processing.

E.g.,

$ zbarimg http://i.stack.imgur.com/pQV0s.png  
QR-Code:hello world

There are several web based QR decoders. Your friend can just upload the image and the service will tell her what the code says.

One of the most popular is ZXing - http://zxing.org/w/decode.jspx

There are also others at

http://www.onlinebarcodereader.com/

http://www.patrick-wied.at/static/qrgen/