There are actually two ways. One is to take a local bus from Livorno to Pisa (about a 15 min drive) but I do not personally know the details of where and when you can get the bus. The other option is to take the train (15 min train ride) from Livorno to Pisa. The problem with the train is getting from ship to the Livorno train station. The most convenient way is to simply grab a taxi from the pier, but the taxi drivers do not like to do this short haul, so you sometimes have to be a little assertive and expect to pay too much (usually about 20 Euros for a taxi for 4). If your ship offers a shuttle into town, you can do that, but its not a great solution since they normally drop passengers in the center of town far from the train station. At that point you still need a taxi or must use a local bus line. Since the cruise lines usually charge for their shuttles, its just better to spend a few extra Euros and take the taxi.