adding user defined option to the windows right clk option

Hi,
I have developed an application shreds files. I wanted to add the shred option when one right clicks on any file or folder. I searched a lot on the net with little success. Can anybody please guide or send me any link where i can find the relevant information.
Thanks, any help would be appreciated.

http://msdn.microsoft.com/en-us/libr...89(VS.85).aspx