We are using a Blackberry 8830 World Edition cell phone in Nigeria which we obtained and are paying for in the USA. We are currently in the small village of Kwarhi, on the grounds of EYN's Kulp Bible College. This is about 13 km west of Mubi in Adamawa State. By comparision, Jos is a huge metro service area.I don't know the cost of the basic voice service plan Tom refers to, but I'm guessing that the monthly total for that plus the data service must be close to $100, currently about 15,000 naira per month, for GPRS (low-to-medium speed) service.
The phone is designed to search for the best available service connection wherever we may be. At different times it has connected to MTN or CelTel (now Zain) while we have been in Nigeria. Here in Kwarhi, and in Jos while we were there, it has connected to CelTel's GPRS system. It took about one minute to download the wiki page you reference in your article.
The phone was purchased in the US for 99 dollars, and we got a 70 dollar rebate. Net cost about 29 dollars. Price probably can't be matched now.
We added the global service to this phone just before leaving the US. I don't recall the sim chip charge--20 dollars or so I think. We are charged 65 dollars a month, on top of our US domestic voice service plan, for unlimited 24/7 email and Internet browsing service in 140 countries with partnership agreements with Verizon Wireless, our US service provider.
We have been very pleased with this service in Abuja, Jos and now in the "bush." It seems to work anywhere there is a CelTel tower.
On the other hand, I've tested the MTN service in the past couple of weeks and it has been unusably slow, both at my home and the office, despite having a strong signal.