asterisk users - Jun 2005 - Driving direction sent to callers mobile phone via text/sms ?

Hi,
I'm wondering firstly if somebody already did this and what the best
way might be to go about it.

Basically I want to have a context in * which could just be a regular
extension that you can transfer an incoming caller to.

This extension could then do several things, the one bit I need advise
on is sending a sms to the
callers cell/mobile phone with driving directions.

1) Firstly it should check the callers ID and see if they are on a
cell phone, if so it could jump
straight to the questions:

"would you like driving directions sent to your mobile phone as a text
message - press 1 for yes, 2 for no" etc

Depending on their input it sends the directions or not.


2) If it does not detect they are on a cell phone (in the UK it could
look for prefix 079* etc)
then it asks the user if they want to enter their cell phone number so
that directions could
be sent as a SMS, so it then reads the users DTMF codes in and sends the text.

I'm using the fastsms agi etc from Bayham Systems:
http://www.bayhamsystems.com/asterisk.html which works well for
voicemail notifications etc, I figured I could use this to send the
directions.

I guess I would need an AGI script to do most of this?

Any pointers most welcome.

thanks
Mike