Want to add the rows data

Question

Hi

I have a problem, want to add row data and GROUP the data by using SrNo
and Months

         SrNo        Months        Value
          1           Jan-2010        2
          1           Jan-2010        5
          2           Feb-2010        1
          2           Feb-2010        6
          2           Feb-2010        2
          3           Mar-2010        7
          3           Mar-2010        4

The result set should be like this:

        SrNo       Months         Value  
         1          Jan-2010         7       (Sum of Jan-2010 value)
         2          Feb-2010        16     (Jan-2010  + Feb-2010)
         3          Mar-2010        27     (Jan-2010 + Feb-2010 + Mar-2010)

Help on urgent basis.
Thanks in advance
Regards
Anurag