I'm getting the idea that pretty much nobody here has actually watched the Jobs' presentation of the iPhone that was linked earlier. It makes clear a ton of the questions and guesses that are being bandied about.

Visual Voicemail is random access voicemail. That's one of the reasons that the iPhone will, initially, only be available on Cingular: to do the Visual Voicemail, they also need support from the provider.

Widgets work much as they do on any Mac, and Jobs shows off a number of them in the presentation. Stocks and weather, specifically, if I remember right.