Here are two excellent sources of information:
Shamanism of Siberia and Central Asia:
http://buryatmongol.org/shamanism-of-siberia-and-central-asia/
Shamanism – Indigenous People of Siberia:
http://www.face-music.ch/bi_bid/tengerism_en.html
The amount of information on these sites is enormous, so it is well worth checking them out!