When in Tallinn, you can use public transportation - bus, tram, tolleybus - or enjoy walking though the beautiful medieval Old Town. For public transportation maps, timetables, ticket information, see here.
Ticket prices for bus/tram/trolleybus from 1 July 2011:
single fare from the bus/tram/trolleybus - 1,60€
single fare from the booth - 1€ or 0,80€ (when purchasing 10 tickets)
1-hour ticket - 1,20€ or 1€ (when purchasing 10 tickets)
1-day card - 4€
3-day card - 6€
5-day card - 7€