So far my favorite knitting podcasts are Cast On (her voice is so soothing), Lime and Violet... these gals make me laugh so hard! And i listen to KnitCast off and on and i have Knitting Psychos on my list which i have not listened too yet.
Non knitting podcasts i listen to while knitting consist of Diggnation (this is for those who are a little bit techy), Deo's Shadow (a pagan podcast), Ctrl+Alt+Chicken (a video podcast thats a tech cooking show... sometimes the meals turn out terrible, its so amusing to watch), The 4th Age (a podcast about Robert Jordan's book Wheel of Time series), And Tiki Bar TV (a video podcast, very silly but i get to learn how to make a new cocktail so yea!). And NPR Environment and It's all Politics.
I really dig the whole podcast thing, there is a podcast on anything you could think of. Along with audiobooks, podcasts are something i really enjoy listening too while knitting, since i don't watch much tv.