From Android, called "I'm Getting Arrested," inspired by OWS:
Users craft a text message in advance and program a list of recipients. Then, as cops get the bracelets out, they can hit one button and tell everyone on their list that they're in danger of being pinched. As of Monday morning, 9,000 people had already installed the app.
From CNET's review:
As you can imagine, I’m Getting Arrested can be used for more than just incidents of wrongful detainment. It’s actually a great shortcut for sending any kind of message in a hurry. It can also be used for messages that you send regularly. For instance, do you send the same text to your carpool partner every day? Well, with I’m Getting Arrested, you can just program it in, and long-press the bull’s-eye instead of typing out your message every time.