09-14-2011 03:17 PM
Titanium is used for creating a native app for various platforms. One good thing about it is that it is that it will generate actual native source code so object C for iphone and java for android and blackberry. You can use that generated source code and build your app from it and tweek it if you like.
PhoneGap from my understanding is just a wrapper around html5 code so you can package your html5 app and sell it on any app store so you are going to be a little limited as too all the actual phones functionality you can take advangate of.
Becuase of some differences between iphone and android with regard to the UI some appcelerator components are only availble on iphone for example as android has a different way of doing things. So there can be litle extra work to support all devices. Luckily you can put predefined statements for different devices in the same code.
Titanium does work best for iphone apps but they are constantly improving their android support. As for bb support I have know idea at this point the state of it currently.