An "entry model" is generally the cheapest and most basic model of a product or device. When they refer to the "entry model" iPhone 4, this would mean they are refering to the 16GB version as this is the most basic iPhone 4 currently available. The term "entry model" comes from the customers' perspective. It is the model that will allow the customer to "enter" a particular product group or segment. In this case, the iPhone4 16GB allows the customer to "enter" the "iPhone owner" group. I hope I haven't overcomplicated this. This is generally a term used in the business world.