Determine device (iPhone, iPod Touch) with iOS

Question

Is there a way to determine the device running an application. I want to distinguish between iPhone and iPod Touch, if possible.

Answer 1

Dutchie432 and Brian Robbins have provided great solutions. But there's still one model missing, the Verizon iPhone 4. Here's the missing line.

if ([platform isEqualToString:@"iPhone3,2"])    return @"iPhone 4"; //Verizon