A more important question is maybe -- "why are you asking"? Could it be that someone has told you yours is faulty? If so, please discuss further!
They're usually on the inner wing, passenger side (assuming RHD) of the engine bay. I think FIAT may have put the early MPI ones somewhere else. If so, find the coil pack (the thing with the ignition leads coming out of it) and thrace the low tension wires back (the LT wires have a two pin pin connector for each coil). The thing you come to will be the ECU. It'll have something like Weber/Marelli and a number on it.