SMS, Wifi, rs232 Arduino Project

Greetings fellow tinkerers,

I am beginning a fairly complicated project and I am new to the Arduino, so please jump in a let me know if this is impossible.

The project in brief : Send a text and change the color of 12 giant public light displays.

Details :The lighting is run with a ColorKinetics iPlayer 3. This can be accessed by a rs232 9 pin input that accepts basic ASCII. The iPlayer is kept in a vault underground.

Method :An Arduino UNO with a Wifi Shield (weburban or WiFly, I have decided), and a rs232 shield (cutedigi one looks good) connected to the iPlayer 3 in the vault.

A Google Voice number that forwards text messages to the wifi shield. (I have yet to find to appropriate program to make this happen. Lots of stuff similar out there but not exactly what I want.)

The Arduino accepts the text, and runs it through a simple program which parses out bad texts and uses good ones (I've written these before), and sends the iPlayer3 the correct ASCII characters to control the lights.

Questions : Does the cutedigi shield convert TTL into rs232? What programs does the community here recommend to test this on my computer (a Mac)? Can the UNO have both a wifi-sheild and a rs232 shield on it? Which wifi-shield is better for this application? How can the wifi-shield receive the text message?

Anything else you folks can think of would be great.