DroidAlone is an application that logs and forwards missed calls and sms to the owner of the phone by reporting caller's name and number by email to a given email address or by sms to a given phone number.
It can be enabled and disabled remotely by sending it an sms.
It also has a configurable automatic "I'm away reply" function to notify the caller with a precompiled sms, and a remote contact number picking function through sms.
Every functionality can be activated or deactivated remotely sending sms containing commands, and a password is required to discard malicious people commands.
More information can be found on the DroidAlone website, http://sites.google.com/site/droidalone/ .