Interesting discussion of the fifth amendment and the use of police information against defendants in the court system by James Duane, Professor at the Regent Law school in Virginia and former criminal defender.
Duane is a wildly hyper speaker, and this is pretty long (27 minutes). But it's chock full of concrete examples and some real eye-openers of criminal law.
Google video here
If you want the really short version without seeing the explanations (which I don't recommend, the examples given are stunning): Nothing you say to the police, even if you are completely innocent and telling nothing but the absolute truth, will ever be used to HELP you in court. Ever.