I need the ability to do the following things:
1) read the phone numbers out of received sms messages.
2) send an sms message.
3) finally, this one isn't necessary but would be a bonus: cause the phone to vibrate.
From what I can tell this wouldn't be possible on iphone or windows mobile, what other phone types cannont do this?
It will probably not work on iPhone, considering the limitation on all applications in an iPhone. (Apps are in their own little world so to speak)
Vibration: All that supports vibration.
Sounds to me like you should focus on Android, where you will be able to do all of your mentioned things.