versions.current()
I also found sys.argv[0] which contains the path to maya.exe. It
depends on where you install your Maya, but the default location will
have 2011, 2012 in the string we can check also.
import maya.cmds as cmds
v = cmds.about(version=True)
print v
please check the about command help from maya you can get a lot of data from the help