Uber

Hi. Just put 'Uber Italy' in the search box and you will see a post from August that answers this. Enjoy your trip!

Here's the post Bob is referring to: https://community.ricksteves.com/travel-forum/italy/uber-in-italy

It was illegal until the end of May. Not sure where it is available at now though.

Uber service driven by ordinary people is illegal in Italy. A court in 2015 established that that type of passenger service can be rendered only by professionally licensed drivers.

Therefore the only Uber service available in Italy is Uber Black, UnerLux, and UberVan, but it operates only in Rome and Milan.

The above Uber services provide a black luxury limo service aboard luxury cars (or Van), driven by professionally licensed limo drivers, which in Italy must have an NCC (noleggio con conducente) license.

The cost is generally higher than a regular taxi. For example I just tested a sample ride from Piazza dei Cinquecento (Stazione Termini) to the FCO airport. I was quoted:
65.74€ with UberBlack
86.38€ with UberLux and UberVan
A regular taxi ride would be 48€ (flat fare imposed by the City of Rome)

https://www.uber.com/ride/uberblack/
http://uberestimate.com/what-is-uber-lux/

Thanks for all the replies. I see that I should not rely on it as a form of transportation around Italy.