SoftBank Mobile has announced (Translated Link) its new “iPhone for everybody” campaign, in which it is offering new customers a free 8GB iPhone 3G with a two year contract. The free handset is available with three different plans, including standard, premium, and student, which range in price from 490 Yen (roughly $5) to 1,960 Yen (~$20) a month. The carrier is also dropping the price on its standard monthly data plan from 5985 Yen (~$61)…