The answer, in short: It depends.
Tethering—using your smartphone as a mobile hotspot for surfing the web on other gadgets, including tablets and laptops—is fairly straightforward on Android, iOS or Windows Phone devices. However, most smartphone prepaid or pay-as-you-go bundles in Italy do not allow you to use the tethering capabilities of your phone.
The same often goes for VoIP apps like Skype.
But there are a handful that allow it (as of February 2014).
Vodafone: Tethering is not included in any prepaid voice, text and internet SMART bundles. However, it is possible to tether by adding an additional prepaid data option called Fly. This costs €20 for up to 7Gb of tethering data (3G speeds) valid for a month. Fly also allows you to use VoIP services.
TIM: The internet portion of TIM’s voice, text and data bundles is compatible with tethering, but not with VoIP calling. For example, TIM Start includes 400 minutes, 200 text messages and 1Gb of data, all valid for a month, for €15. You can also extend the data portion of the tariff with an additional 1Gb “Internet Extra” for €5. Standard TIM internet add-ons, however, such as “TIM per smartphone” (€3 per week for 300Mb), are not compatible with tethering. If you want VoIP calling, too, you’ll need to activate the Internet 4G option: an additional 15Gb of 4G internet a month for €35 or Internet Large (5Gb/€20).
There is even more choice if you carry an unlocked MiFi or personal hotspot device. I’ll cover that in another post.