Ringtone Download Service Startup

You need to contact each of the 4 Nigerian GSM networks and ask them for details on how to be a 'Wireless Application Service Provider' (Vmobile) or 'Content Service Provider (MTN).

With the advent of free ringtone download websites on GPRS-compatible networks, I don't think such a venture is likely to be profitable.  The Nigerians I know will not pay 100 naira for something they can get for free!