Inbox, a gesture driven email application from the Gmail team built on Google-acquired Sparrow technology, got refreshed with new features this morning starting with Undo Send. Now, Undo Send has been available for quite some time through Gmail's web interface.
Now for the first time on your iPhone, Undo Send lets you take back an email right after sending in case you spotted a mistake, or have second thoughts. Also important, Inbox is now open to everyone so all Gmail fans can get in on the action right away.