If you had to convince someone, given that that person was somewhat intelligent, unbiased, and had a basic understanding of biology, that evolution was sound theory, where would you start?
I would start with Douglas Theobald's essay to which Modulous linked above. I gives a sort of broad over-view of the evidence in favor of evolution, and presents in it prediction-confirmation style -- you can also use this to discuss what science is in general and how it operates. The problem with most creationists' perceptions of the theory of evolution is that they usually don't understand how science operates, and they don't understand how the theory of evolution fits into this general operation.
If you want more specific examples of particular observations and experiments within the the general areas that Dr. Theobald describes, then molbiogirl's post will help you find more detailed information.
Spare a thought for the stay-at-home voter;
His empty eyes gaze at strange beauty shows
And a parade of the gray suited grafters:
A choice of cancer or polio. -- The Rolling Stones
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