WORD UP is the most informative and authoritative podcast on the topic of scrabble ever recorded.
Actually, I'm just a hack player who lives in western Massachusetts (in the U.S.)- I've been addicted to competitive scrabble for a couple of years now; I started the podcast because I found it to be a fun way to learn new words and because, well, no one else was doing it.
I don't claim to be an expert by any means; I started the podcast as a experiment documenting my progress in scrabble, and it's continued on from there. I try and make each podcast a fun way for people of all skill ranges to learn new words, as well as including a few other tips. I always welcome emails at firstname.lastname@example.org.
Find the podcast here, or here, if you aren't an iTunes person.