How can I get the cumulative sum of a field in a table

For Eg.

I have a table like gias given below:

Name                  Amount

------------------------------

aaa                       10

bbb                      20

and I want an output like one given below on running SQL query or stored procedure

Name                  Amount                  cumulative amount

---------------------------------------------------------------------

aaa                       10                              10

bbb                      20                              30

can anyone plz help me on this