Milan is the most busy city in Italy. Home to some of the major company’s it is regarded as the capital of finance and lifestyle.

Public transportation is managed by ATM - http://www.atm-mi.it/en – and includes buses, metros (tube) and trams (railbuses).

The tube (metro) has 4 lines:
linea 1 – the red line
linea 2 – the green line
linea 3 – the yellow line and the recent
linea 4 – the blue line
They cover the entire city area and part of the suburbs.
Metros are open roughly from 6 am to 1 am, but do check updated timetables on the website or at any station.
Metro entrances are marked with a red square sign with a white "M".

Trams and buses run overground and cover also some areas that are not reached by the tube.
Tram stops as well as bus stops are marked by tall orange poles with a diagram of the tram or bus route.

Busses are usually orange. There are electric cable busses as well as independent busses. Between all systems of public transport you can get just about everywhere in Milan.

Urban tickets cost 1 euro and let you ride throughout the entire urban area for roughly 75 minutes, on metros, buses and trams. You can only enter the metro gates once.
A "2x6" - can be used two rides a day for 6 days aweek and it costs: 6,70 euro.
Weekly pass costs 16,75 euro.
Monthly pass costs 37,75 euro.

Please check updated rates.
http://www.atm-mi.it/ATM/eng/Muoversi/Biglietti/