Multiple group by and Sum LINQ

I have a products sales table that looks like this:

saleDate     prod        qty
10/22/09     soap        10
09/22/09     pills       05
09/25/09     soap        06
09/25/09     pills       15

I need to make the SUM of each MONTH so the final table would look like this:

saleDate     prod        qty
10/09        soap        10
09/09        soap        06
09/09        pills       20

Can I do this with LINQ?