Intercept Incoming SMS Message and Modify it

Is there a way to intercept an incoming SMS message, and then modify it before presenting it to the user?

• Can it be done natively on iPhone / Andriod?
• Can it be done using PhoneGap?
• Can it be done using MonoTouch / Mono for Andriod?

If yes to any of the above, could you please provide some pointers to it?

My preferred-solution priority-order is as follows:

1. Phonegap
2. Mono
3. Native

Thank you all in advance!!

EDIT:

For people wondering what is the purpose of this, basically I would like to put a word as a "label" in the sms depending on the content, so when I view the sms, I can see something like "IMPORTANT: blah blah blah", instead of just "blah blah blah".