Warren, N.J. - Virgin Mobile USA, the wireless telecom services provider, has signed a deal to acquire Helio, a wireless services joint venture between EarthLink (NASD: ELNK) and SK Telecom, for about $39 million in Virgin Mobile stock. Helio has about 170,000 existing subscribers with an average revenue per user of about $80, and a handset inventory of about 85,000 units with a book value of about $17 million. read more ...