Here's this thing I found in Mashable today:
Here’s how it works: Users or venue owners can generate a printable 2D barcode — using the venue address or Foursquare ID — and stick it on the venue in question. Visitors can then use the Android application [download link] to snap a photo and scan the code. The scan automatically pulls up the venue in question in the Android Foursquare app for a faster checkin.
Here's my important thoughts on the topic. I'm really knowledgeable, so pay attention to what I say.
