From these screenshots taken from the iPhone 3G Guided Tour video, we can confirm that the Twitteriffic, TypePad, eBay, and AIM apps will all be free. The Super Monkey Ball app/game will be $9.99.

When you download an app, it’ll appear on the homescreen as an icon, and it’ll say Loading… or Installing… with a progress bar on the icon. When it finishes, you can toy arround with your new app