For the past couple of months, the U.S. Postal Service has been running this print advertisement, which features a QR Code. The ad promotes the USPS's priority mail flat rate shipping option and ties in with other marketing channels, namely television.
The one comment I do have about the campaign is that on the mobile website the contact form defaults to "at work" and not "at home." If a consumer skips this step they might not realize why an error message keeps coming up saying that "some fields are missing required data." A radio button or check box for the at home/at company option should have been considered.
On another note, you may find this campaign from the USPS of interest, it's called the 2011 Mobile Barcode Promotion.
2D Barcode Litmus Test: PASS