Lake Como is navigable by car, boat or train. Ferries dock for passenger service in Bellano and Varenna for cartransport across the lake.
The trainstation in Bellano (Bellano-Tartavalle Terme) has direct routes to Milan.
Here are some of the most useful links for transportion.
The public ferry service on the lake Naviagazio Laghi: link
Private boat tours: link
Train service TrenItalia: link