For the WWF Germany Tiger Campaign, WWF used QR Codes next to SMS. Heldisch has made the campaign and used Kaywa's QR Code Management solution for it.
Contributions with QR Code/SMS only work in Germany, as all this is done directly via Mobile (see iPhone Screenshot below).

Here is the QR Code:



And the result on an iPhone:




Images used from :
Heldisch, Tagmotion and Mobile Marketing Welt