I've never did any podcasts but I've observed and listened during ones my cousin did with a group about MMOs.
Tips to get started:
>Get your hands on a good mic and practice a bit maybe using group Skype sessions
XBL mics and cheap gaming stuff are often pretty terrible sound quality and it'll come across when you re-listen for editing. Whatever you have to start is fine but down the line if you want to keep going a good mic is highly recommended.
>Plan out your script in advance in terms of the things you want to discuss but leave it flexible
Mostly a list is just helpful for having the bullet points of what you want to discuss, everything else can be (and is often better when) composed on the fly during organic discussion.
>Make sure you have a core group that can show up and actually talk at the designated time
Most of the ad-hoc newbie podcasts that I've listened to or heard being organized fall apart because of this. Special guests are fine and if you have to rotate the cast for life reasons that's okay too, but the best podcasts consist of a regular group of people that mesh well and the audience can identify with.