One question that came up at a user group recently was how on earth do you keep up on the ever-changing Salesforce. One way I do it is by listening to podcasts on Salesforce. There are now quite a few good ones out there. If anyone knows of any more please let me know!
UPDATED 1st Nov 2015: Added YappExchange, 12th Sept 2015: Added Technology Flows. 1st Sept 2015: Added WizardCast, GoodDaySir Podcast & NerdForce Podcast.
A great developer podcast run by two great MVPs Steven Herod & Matt Lacey. This podcast has had a load of great developers talking about how they use Salesforce. Reid Carlberg, Andrew Fawcett, Keir Bowden, Josh Birk to name just a few.
Run by the great admin guru of them all Mike Gerholdt. He started off running the site while he was a Salesforce MVP but it became so successful he joined Salesforce and is now a Salesforce Admin Evangelist and the site is run by him at Salesforce. Focused more around Salesforce Admin this is a great podcast to keep up to date on the declarative side of Salesforce but have some great guest speakers as well as some great blog posts.