I have a website which sells a product to the user (downloadable). I am creating an iPhone app and want to be able to sell some of the products using the 3.0\'s in-app purchase.
As I understand it, no - all the things you want to sell via in-app purchase run through a vetting process similar to that of the apps themselves. Apple won't allow, for example, a "photo of the day" application if you can in-app purchase pornographic photos to be sent to you daily.
What you could probably do is submit your app with a backlog of in-app purchases, five or six days ahead of time, then consistently be submitting your daily items ahead of when you want them to be available. Not sure how reliable the review process is, or whether this will work for your situation - just a thought.