in the book <把你的英语用起来>, the author mentioned one good podcast which is good for us to learn American English everyday.
you can download an app called "Podcast" and search "ESLPOD" in the store,
or you can directly listen to their program online (http://www.eslpod.com/website/flash_player.php?issue_id=13990003).
and their homepage is: http://www.eslpod.com.
try to listen to this program everyday.