Creating a Graph in Excel using drop downs

I have a file, that we are tracking leads. In the file, we have several components, but 2 specific components I'd like to graph. We have a Date Column(which includes the date as follows: 3/6/2010, 4/1/2010, 4/7/2010, 5/1/2010, etc - so different months on the same worksheet). And a Source Column. The Source Column has a drop-down list to choose where the source came from.

1) I'd like to create a comparison graph that shows as follows:
--The Vertical Access would show the # of Leads
-- The Horitzontal Access would show the Type of Lead
-- Each Lead type would have a Bar Graph of the # of leads per month (so if doing January, February, March and April, each horizontal lead type would have 4 different bars (each month) showing it's progress.

Please help!