It works for me:
>>> import rpy2
>>> import pandas as pd
>>> import pandas.rpy.common as com
>>> rpy2.__version__
'2.3.1'
>>> pd.__version__
'0.10.0'
>>> datframe = pd.DataFrame({'a' : [1, 2, 3], 'b' : [3, 4, 5]})
>>> r_df = com.convert_to_r_dataframe(datframe)
>>> r_df
<DataFrame - Python:0x105b12710 / R:0x7fa8131d7918>
[IntVector, IntVector]
a: <class 'rpy2.robjects.vectors.IntVector'>
<IntVector - Python:0x105b12ab8 / R:0x7fa8131d7838>
[ 1, 2, 3]
b: <class 'rpy2.robjects.vectors.IntVector'>
<IntVector - Python:0x105b12950 / R:0x7fa8131d7800>
[ 3, 4, 5]
Different rpy2 version though..