SQL & PL/SQL

I'm stuck with decode() function:

I have a table like this:

(project_id, approve_date, value, builder_code)

I want to write a SQL query to get sum of values for different month of the approve_date, and group by builder_code)

The result is like this:

builder_code Sum(value)_Sep-03 Sum(value)_Oct-03 Sum(value)_Nov03
1001 1,299 1,322 990
1002 3,332 1,222 333

I tried to use decode for this question but could not get the answer.

Thanks a lot