EDIT2: This giveaway has concluded. Thanks to everyone that entered or purchased the book through the TA Radio Show bookstore! Tune in to the show to hear the winners announced! EDIT!: The giveaway is now LIVE! The contest entering tweet is: I'm a member of @ThinkAtheist and I want a copy of Lawrence Krauss's "A Universe From Nothing"! http://bit.ly/xlWb4w #atheism #science Follow the instructi…