Great source of information for any biome:
http://ths.sps.lane.edu/biomes/index1.html
http://www.ucmp.berkeley.edu/glossary/gloss5/biome/tundra.html
http://www.cotf.edu/ete/modules/msese/earthsysflr/tundra.html
http://mbgnet.mobot.org/sets/tundra/index.htm
http://www.cotf.edu/ete/modules/msese/earthsysflr/taiga.html
http://mbgnet.mobot.org/sets/taiga/index.htm
http://www.cotf.edu/ete/modules/msese/earthsysflr/dforest.html
http://mbgnet.mobot.org/sets/temp/index.htm
http://www.cotf.edu/ete/modules/msese/earthsysflr/rforest.html
http://mbgnet.mobot.org/sets/rforest/index.htm
http://www.cotf.edu/ete/modules/msese/earthsysflr/desert.html
http://mbgnet.mobot.org/sets/desert/index.htm
GRASSLANDS
http://www.ucmp.berkeley.edu/glossary/gloss5/biome/grassland.html