In Tech Talk world Tour 2009, a large number of sessions were presented that concentrated on developing quality apps to the iPhone users. Today, Apple has made them public, by making it accessible to all iPhone developers to learn, enrich, and qualitatively build new iPhone apps.
“The iPhone Tech Talks provide you with guidance, insight, and advice on how to take your app to the next level. Kick off the day with key recommendations for your development and learn about the powerful technologies you’ll use to create great iPhone applications.”
Prior to this, Stanford university published a Video series on How to Write iPhone Apps [Tutorial]. It’s worth checking out too.