If you want to send a package from Italy - perhaps you have bought too much stuff on holiday - you'll find it can be surprisingly straightforward and fast. This week I sent a big box of books from Venice to London on Monday and they arrived today (Thursday).
The easiest way to do it is to buy a standard yellow box (scatola) from an Italian post office. They come in different sizes, with security tape and a space for writing the destination (destinatario) and the sender (mittente). I think I paid around €3 for my box. I put my books in an old pillow case to keep them together and added the destination address to the top of the box in black marker pen.
At post offices in Italy you are usually expected to take a numbered ticket from a machine (for servizi postali) and wait your turn. You'll need to fill in a form detailing what is in your box. For Europe this isn't too demanding, though I did have to guess the number of books I'd packed. If your box is going outside the EU, you'll need to complete further customs declarations.
For the EU there are two options for sending parcels. The standard service takes 10-15 working days. Quick Pack Europe, an express service, takes 3 working days. Between Italy and the UK there wasn't a big difference in price between the two services, so I paid €50.42 for Quick Pack Europe. As promised, the books have turned up within three working days. At a cost of approximately £39, this seemed a pretty good service.
> Prices for Quick Pack Europe
> More about the service (in Italian)