The word "podcasting" is a portmanteau of "ipod" and "broadcasting".
Podcasts are like radio programmes but on the interweb. Subscribe to a podcast and a new episode will be downloaded when it's published. You can then listen to it at your leisure.
Although podcasts are like radio, it's incredibly important they shouldn't feature as high production values as radio programmes, they shouldn't be slick, they shouldn't feature adverts or professional DJs or voice artists. That's cheating. Also, if a podcast appears to have been made by chopping up the best pieces of a proper radio show, well that's a serious offence and baby jesus will, somewhere, be shedding a single, opaque tear.
As you can see, it's complicated (and, although I shouldn't be telling you this... it involves copious use of smoke, mirrors, secret trapdoors and twins).
Most people refer to the iTunes for their podcasting needs. But you can use other software (Juice is a good one).
You'll need the feed to subscribe to the podcast: here it is.
If you need more sensible help, try these:
Who are Gareth and Nick? Why should you trust them? What's their favourite colour?