The itertools module has lots of great stuff in it. So if a standard slice (as used by Levon) does not do what you want, then try the islice function:
from itertools import islice
l = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20]
iterator = islice(l, 10)
for item in iterator:
print item