There are different ways to do it so you'll have to decide and them move forward.
First, you'll need to add the employee as a parameter to your report.
Then you can either use the ReportViewer control and pass in the parameter using the value from the drop down or you can use the url to the report and pass the parameter that way.
One example:
http://msdn.microsoft.com/en-us/library/ms155391.aspx[
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Many more examples online if you decide which way to go.