Hi
If you encounter too many problems with getting PRS/Label clearance for your tunes, it might be worth hosting your podcasts on something like Mixcloud, who deal with all that malarkey for you. The only downside is that the mix can only be streamed, not downloaded like usuale podcasts. However, the mix is easily embedded onto websites and and facebook pages so meets the need for marketing etc. I rarely download mixes now as my hard drive would be too full, I just favourite and on with the next – Ive got more than I have time to listen to and assume the same for those listening to mine.
On the second note of making a podcast I would recommend starting with the free Audacity and a cheap headset. Just import your mix into it and record a voice over into a separate track, you can also slit your mixes up for pauses and use another track for jingles etc. cheap but effective.