Best of the Left is my favourite podcast. They have an iPhone app as well and I listen to that all the time. Some dude basically throws together the best of the left media in ~5 minute clips and he puts three or so shows out every week. He has clips from Colbert, Daily Show, Bill Maher, Rachael Maddow, Wait Wait, Young Turks, and a ton more.
http://www.bestoftheleftpodcast.com/