I'm always looking for freebies to try out and, perhaps, keep and use. Not that those are the best answers always, but it's a good first start. One great thing about Podcasts on Apples iTunes is that they are FREE! You can in some cases read [aurally] entire books and there are podcasts that go on 1-2 hours, perfect for a long drive, or are videos which work well on your iPod or iPhone if you're on the plane. I'm going to list here some that I've found informative and exciting over the years. Personal preference only, but worth checking out [I'm listing only those which might be of general interest, to whet your appetite]:
Visual: Hidden Universe HD & Hubblecast [from NASA and its telescopes], The New Yorker Animated Cartoons
Fun: Last Minute Book Reports [really, Moby Dick in 2 minutes?], Stuff You Should Know
Educational/Informative: LearnOutLoud's Biography Podcast, The Best of National Geographic Magazine, Bill Moyer's Journal and NOW on PBS, NPR's shows [Driveway Moments, Science Friday, Fresh Air], This American Life, 60 Minutes
There are, actually, too many choices!! At least I have a 160G iPod to back them up to and play them with. I wish I had more time [perfect for commuting time]
[and, yes there are lawyer's and law-related podcasts as well!]