"A web-based portal lets developers manage a large number of business and store presentation elements. It also lets these creators set the compatibility of the app with the iPod touch, the global regions where program should be distributed, and even game content ratings that roughly match American and European standards, warning parents of particularly sexual or violent content during play."
If you decide to charge for your application, Apple is using a tiered system. You can ask users to pay as little as 99 cents at the US store up to a maximum of $999.99; each tier moves the price up by increments from between $1 to $100 depending on the relative price difference.
It is likely that the AppStore will open July11th along with the launch of the 3G iPhone.