San Diego-based Leap Wireless (NASDAQ: [[ticker:LEAP]]) today is launching its Cricket unlimited wireless service in the greater Philadelphia area. That’s the second major market the low-cost wireless provider has entered since January, when Cricket began service in Chicago. The company, which announced its move yesterday, is now forecasting 5.3 million subscribers this year. At the end of 2008 it had just 3.8 million subscribers in 29 states. Cricket provides unlimited, low-cost 3G wireless voice and broadband services, with monthly rates that range from $30 to $60.