Acutally, you both have already forgotten Symbian (Take a look at the the table!)
The symbian share is falling much faster than Nokia's WP 7 sales are growing.
This and Windows Mobile. Windows Phone is effectively an inheritor from both systems and should be inheriting the combined market share. It's rediculous to look at just Windows Phone's share alone ignoring the fact that there is already an established channel to market and set of shops and distributors which should be pushing the phones at the same rate as the models they are replacing.
On the list of things keeping children in poor countries from getting an education, lack of laptops is way towards the bottom.
The thing which is missing is access to information and various tools. A computer is a good and cheap way to deliver information when textbooks aren't available and is a good and cheap way to deliver tools such as calculators; word puzzles and so on when those aren't available. These aren't really that much available in a standard base OS install that you would see, but OLPC provides a custom environment where they are available.
You'd get far more bang for your buck with desktops.
I suggest you have a look at the OLPC FAQ, which explains this stuff. Desktops require large amounts of continuous power, which just isn't available in the environment these places are designed for. Laptops with batteries and low power usage just work better here. These students often simply don't have a space where they could put a desktop anyway.
And most of all, every time I read about OLPC, it's always about the tech and the specs, not how it actually helps kids. That strikes me as techno navel-gazing at its worst.
You are reading about OLPC on Slashdot "techno navel-gazing at its worst" is our hobby. Perhaps you should go and read about this from the people who are actually doing it.
Until I actually read or see a story that details the benefits to real children (and please, feel free to send those links), I'll keep assuming that this is first and foremost about people finding ways to make themselves feel good about what they do.
The OLPC has a stories page on their front page. That's probably a good place to start. Beyond that they have a bunch of mailing lists where you will be able to find a whole load of stories. However, be aware that there probably hasn't been much reason to direct detailed information towards those like yourself who aren't involved or volunteering so you will find that you have to dig through all the individual country level lists in different languages. These seem to be more active than the top level ones.
Then sell it with no support whatsoever.
For very good reasons, most consumer protection laws don't allow this. If the customer says the system was broken when deliered you have to replace it. At that point, you need to provide enough support to find the power switch otherwise your costs will rocket. At that point, you are providing support no matter what.