The following is taken from http://pandas.pydata.org/pandas-docs/dev/indexing.html. There are a few more examples... you have to scroll down a little
In [816]: df1
0 2 4 6
0 0.569605 0.875906 -2.211372 0.974466
2 -2.006747 -0.410001 -0.078638 0.545952
4 -1.219217 -1.226825 0.769804 -1.281247
6 -0.727707 -0.121306 -0.097883 0.695775
8 0.341734 0.959726 -1.110336 -0.619976
10 0.149748 -0.732339 0.687738 0.176444
Select via integer slicing
In [817]: df1.iloc[:3]
0 2 4 6
0 0.569605 0.875906 -2.211372 0.974466
2 -2.006747 -0.410001 -0.078638 0.545952
4 -1.219217 -1.226825 0.769804 -1.281247
In [818]: df1.iloc[1:5,2:4]
4 6
2 -0.078638 0.545952
4 0.769804 -1.281247
6 -0.097883 0.695775
8 -1.110336 -0.619976
Select via integer list
In [819]: df1.iloc[[1,3,5],[1,3]]
2 6
2 -0.410001 0.545952
6 -0.121306 0.695775
10 -0.732339 0.176444