The last one is to lake Baikal. You can reach any small railway station near Irkutsk. There are a lot of hydrofoil routes down the river Angara and up to lake Baikal. They exist only in the summer time. City's public transport Click here for the city map.
Tickets are the same for all three.
They can be bought in a 10-pack from the driver, at some kiosks, or at kiosks situtated near bus stops. To validate your ticket, slide it into the top of one of the devices mounted on the walls, and punch it. During the day, especially in the centre, these forms of transportation can get extremely crowded. If someone hands you their ticket, they want you to pass it on towards someone standing near a puncher, or if that person should be you, to punch it for them and pass it back. If you travel without a ticket and an inspector catches you, you will be fined 20,000 rubles.