mixture
It is un-necessary to utter the (technically incorrect) statement above
Since you probably don't know how to write Objective-C (assumption made because if you did, you would know the answer to your question), its irrelevant whether or not you (or someone else) can write something for the iPhone.
I don't want to play you in your own game unnecessarily but how the hell do you get user code (or any code other than an app from the Apple shop) into an IOS device
unless it is jailbroken?
FWIW, a colleague of mine who used to develop for a Pocket/PC (Windoze Mobile) device reckoned it would be a few hours' work. But then he was used to writing very low level (block device driver) code for it.
Android is, I assume, very different from WM.
Milo Minderbinder
Well, yes, but there are no bare satphones that do that.
The satcom business is suprisingly behind the times.
The "professional market leader", Iridium, offers 2400 bits/second. Not kidding. This is DUN, no "network" connection like GPRS or 3G. But you get worldwide coverage.
Thuraya offer DUN at 9600 bits/sec (you dial 1722 to get their "in-house ISP") and they also offer a version of GPRS which gives you about 20-40 kbits/sec (and you dial *99# as usual to get the connection) but my tests showed it to be reliable in 2009 and crap ever since, and being Arabs and with the apparent target market being the millions of semi-nomadic Beduins (sorry, but this is what their adverts show) they probably can't see why they should fix a service mostly used by the infidels
There are "boxes" which use dial-up satphones to provide (essentially) a WIFI access point. This is for the "not quite downmarket" yachting (sub £1M gin palace) community where, obviously, you must have WIFI on the boat. But I don't want yet another "box", and WIFI involves quite high power which is something else to consider in a GA cockpit...
For £100k+ you can get airborne and marine fast broadband solutions... I think they are mostly Immarsat ($$$$$$).