You should be able to use .xs
or .ix
in the following way:
print df.ix[(10223,'2011-07-21'):(10223,'2011-07-30')]
values
id date
10223 2011-07-21 24.70
2011-07-22 25.26
2011-07-23 25.28
2011-07-26 25.37
2011-07-27 25.29
print df.xs(10223,level='id')
values
date
2011-07-21 24.70
2011-07-22 25.26
2011-07-23 25.28
2011-07-26 25.37
2011-07-27 25.29
See here for more information