hi all i'm a napoli fan.
I live in the sorrento peninsula.
I wanna just give you awelcome you in naples and give you a pair of useful (I hope) tips, cause last year was very frustrating what happened to liverpool fans.
I hope the atmosphere will be different this time.. in any case it's always better prevent..
These tips are obviously for the ones who are not looking for troubles: first of all I would recommend you to absolutely avoid the area of Piazza Garibaldi (garibaldi square). Don't book there, don't go there.
If you remark an hostile clima, take a low profile, especially in the historical centre or in the area near the stadium, would be better don't wear colours, don't chant. In Naples is absolutely unusual seeing away fans walking in the stadium area or in the city wearing colour (when they come, if they come, they are always accompanied by a lot of police).
It's not absolutely to scare you, but just to avoid some accidents, if the atmosphere will not be good.
If you're planning to stay here some days, you could profit of this to visit some meravellous places.. the city of Naples is very interesting (especially the historical centre), the Vesuvio Volcano, then you have in the province Sorrento, the islands of Capri, Ischia, the breathtaking ruins of Pompeii, the splendid Amalfi and Positano coast (a panoramic drive of unbelieveble beauty)
For the ones who are planning to sleep in Sorrento: there are no transport after the match from Naples to Sorrento (expect hyperexpensive "tourist trap" taxis). It would be probably better spending a night in Naples or hiring a car in Sorrento (in this case drive to Naples in the morning, cause the traffic will be probably in tilt fro mthe early afternoon)
Hope this helps. if yo uhave any questions just ask
Cheers!