import modules you need

#read the file here. there should be examples around (basically open, read, close)
#example, http://www.network-theory.co.uk/docs/pytut/MethodsofFileObjects.html
#lines should contain the read lines. or could handle some other way

coordlist= []

for line inf lines:
  xyzcoords= []

  coords= line.split()
  xyzcoords.append(coords) #check that appends like [item1, item2, item3] ! not 100 % sure about this
  coordlist.append(xyzcoords)

print coordlist # should contain list containing xyz coord lists

#use coords to plot