One other small bit of advice - get you DH or PILs to do your documents or you will go mad. Italian bureaucracy is horrific, although it has improved a bit over the years. Maybe things are not so bad in a small village, but in big towns for instance you have to be prepared to waste a lot of mornings.
I presume your DS has Italian nationality? Did your DH sort out docs when he was born? If not, to register with a paed you need to get him a codice fiscale (like a NI number), then apply for a tessera sanitaria. You get a piece of paper right away and the electronic card comes later through the post (or at least that's how it works in Lombardy, but Trentino shouldn't be much different). You can choose your paediatrician when you apply for the tessera sanitaria. You'll also need to get residency sorted if you want to try and put him in the local state nursery.
Agree with what Rosa says re stocking up on certain things, although you can get Marmite, PG Tips, Rowntrees jellies etc at ethnic shops (the Sri Lankans love them!) and weetabix and Twinings for instance is available at most big supermarkets. Or at least it's like that where I live...
Re telly, as everyone says you get most of the same US series as the UK, albeit a season or 2 behind. Don't know about original language, I watch everything in Italian anyway and to me it sounds really strange hearing the actors' voices in English. I'll never forget seeing ER in English years ago and being hugely disappointed by George Clooney's squeaky voice, it was much deeper and sexier in Italian!
Can't advise on the move as I came out here with a backpack only many years ago.
Anyway, good luck, it'll be a positive experience