I know there are people out there that listen to hundreds of podcast's. I don't. I've downloaded and listened to bunches of them, but there are two that I listen to regularly.
Fat 2 Fit is a great podcast for people who are looking to lose some weight OR tone up and be healthier. Remember, you can be normal-weight but have a high BMI (think "soft" thin people")
Marathon Talk is a show with two (tri)athletes who interview different elite athletes and talk about training, give weekly news about races and racers... Its pretty great. I'm not planning on a Marathon in the near future, but I still love this podcast. It keeps me interested and excited!
Those are just two suggestions I'd like to make for anyone out there who is looking to get in shape and find inspiration! Download a couple shows of each, see what you think.