Virgin Mobile, a pay-as-you-go brand of Sprint, will soon announce plans to offer the iPhone on its network starting as soon as July 1, according to a new report. Citing people familiar with the company’s plans, MarketWatch reports that Sprint is expected to make an announcement about its plans this week. The report suggests that the launch of the iPhone on Sprint’s pre-paid brands may help satisfy its substantial purchasing commitment with Apple. Notably, a report from earlier this week claimed that another Sprint pre-paid brand, Boost Mobile, would begin offering the iPhone in early September; that report was quickly refuted. Pricing for the iPhone on Virgin Mobile remains unknown, although pre-paid carrier Leap Wireless—who will launch the 16GB iPhone 4S on June 22 for $500—may provide a clue as to what to expect from other pre-paid iPhone launches.