As previously rumored, Virgin Mobile has announced that it will launch the iPhone 4 and iPhone 4S on Friday, June 29. The carrier, one of Sprint’s prepaid brands, will charge $649 for the 16GB iPhone 4S and $549 for the 8GB iPhone 4, but will offer plans for as little as $35 a month. That low-end plan offers 300 voice minutes, unlimited text, and unlimited data—which is capped at 2.5GB of “full speed” data. The most expensive plan—which runs $55 monthly—offers unlimited calling, text, and data; the company will offer a $5 monthly discount to customers who sign up for automatic monthly payments. Mobile hotspot service will also be offered for an additional $15 a month, but will expand the “full speed data” cap to 3.5GB per month.