From my friend Andi Arndt comes the following excellent information:
If you can read IPA (International Phonetic Alphabet) or have a good ear for accents, you might enjoy practicing dialects of English at http://accent.gmu.edu/ where there are examples from all over the globe! Another great source is Paul Meier’s website at http://www.paulmeier.com/ which has great resources and links to all kinds of accent-related information.
Thank you, Andi. Good stuff.