Thanks for your replies gentlemen. I also completely overlooked (until I 
checked just now) the fact that there's no iPhone app dev tools for 
Windows, unless you get into jail broken devices and other weirdness.

My client's idea was for a purely software solution on the iPhone end. 
I'll throw this info back to him and see where it takes us.

With the SMS modem option., I checked and it seems that it would cost 
$15 AU per month + $0.15 per SMS via Three for the SIM card. Telstra 
(the national carrier) couldn't even manage to actually answer my calls 
after two attempts so I gave up on them! The modems are a few hundred 
dollars (1-off) and only draw about 10mA when idle, which is not too bad 
I guess.
David...

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___________________________________________
David Duffy        Audio Visual Devices P/L
Unit 8, 10 Hook St, Capalaba 4157 Australia
Ph: +61 7 38235717      Fax: +61 7 38234717
Our Web Site: www.audiovisualdevices.com.au
___________________________________________

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