Getting there by plane
Taking the plane is probably the fastest and maybe also the most comfortable way to go to Siberia. Almost all European airlines and also some Russian ones offer several flights to either Moscow or St. Petersburg each day.
Most of the other Russian airlines (e.g. S7) heading to Siberia depart from Domodedovo airport. Since you are a low budget backpacker, you probably don't want to take the overpriced shuttle service. It is much cheaper and probably far more exciting to take the bus. Again it is Nr. 851 that you have to catch. Take a ride till you reach the last stop "Rechnoi Voksal". From here take the metro (Samoskvoretskaya Line), cross the city and jump off at Domodedovskaya stop (almost last stop). Now catch a shuttle bus to your terminal.
Moscow is a huge city and distances between the airports are quite far. Allow the bus driver about 60 min for going to Sheremetyevo I and II airports and 90 min to Domodedovo airport from the city centre. Alternatively you can take a private shuttle bus or taxi cab, which are often exorbitantly expensive and in no case faster than the metro.
Each day, there are several flights going from Moscow to most of the bigger cities in Siberia. The aircrafts to Irkutsk are generally older versions of Tupolevs (type TU-154). They are fairly noisy and maybe you wanna consider to take a course in "how to handle claustrophobia" before going on the plane, because there is not too much space between you and the sweaty shirt of your neighbour...
Aviations you might choose to fly within Russia are Aeroflot, S7 (see www.s7.ru), Transaero, or Yakutia. To Irkutsk it takes you 5 1/2 hours and is 5 hours ahead of GMT. Aeroplanes usually start in the evening and land in the early morning hours. It's definitly worth considering to split your flights, because in the mean time the number of special fares to Moscow or St. Petersburg from anywhere of the world has increased to almost innumerous offers available.
