This question:
http://stackoverflow.com/questions/2228982/launch-iphone-app-from-link-in-email
suggests that it's possible to launch a particular iPhone application from a link in an email. Is it possible to include an app-launching link of this type in a text message, so that the reader has the option of pressing it (and launching the app) in the same way that they can call a phone number in a text message?