So I am looking around for netbooks and most of the ones I find have core duo or the processor speed is given in GHz, I only know about i3 and i5 and i7 processors and personally say that i3 is better than core duo but I am wondering, is 1.66GHz processor good / better / faster than an i3 processor?
The truth is it depends on what you're going to use it for. Multi-core processors for instance are good for applications which require multiple threads of execution, as multiple threads can be executed concurrently. Something like that is going to be useful for web browsing, because lots of different threads are going to be spawned. Compare that to a CPU-bound application like video rendering where a single thread is going to run on a single core in a multi-core environment (where an individual core has a lower processing speed than a single core processor).