Howard Tayler and Dan Wells have Eric Flint and Mary Robinette Kowal as their guests on the Writing Excuses podcast!
Eric talks about 1632, Shadow of the Lion, Crown of Slaves, and other things while providing insights into writing alternate history and why he enjoys it.
Go listen. About 20 minutes. http://www.writingexcuses.com/2011/01/23/writing-excuses-5-21-alternate-history/