PDair has introduced a wide variety of cases for the iPhone 3G. In leather, the company is offering two vertical flip-style cases — one with a snap closure and one without — in both standard and crocodile-textured leathers, and in a variety of colors. Both flip cases feature open access to ports and controls, and contrast stitching. The Flip Type case with snap closure sells for $28 with standard leather and $32 with crocodile patterned…