Please see the
Site FAQ and
this page in particular, for guidance in posting your questions.
While we are willing to help with specific problems, asking for others to read and modify your code is not a good way to approach a solution. Please show us what you have done and at what point you are having difficulty first, then someone with the relevant knowledge can help you past that point.
Also be sure to use your search engine of choice to find online resources, there are many for leach and ns2!
A quick search for ns2, leach and aggregation here on LQ also turns up a number of relevant threads as well.
This one has very good notes and references for leach implementations, including aggregation integration.