The title pretty much asks it all :) Thanks.
Nevermind… I figured it out. For anyone else that is interested it's in the Titanium.Platform obj
Titanium.Platform.model is 'Simulator'
Titanium.Platform.username is 'iPhone Simulator'
1.7.2 has changed things so that Titanium.Platform.model is now set to 'iPhone Simulator' when running in the simulator. Why the change? - that broke all my code!!
A colleague I work with has to look for this value from Ti.Platform.model when checking to see if the app is running in the simulator… 'x86_64'.
For me the iPhone simulator shows as 'Simulator'.