One short follow-up: I did a little more research, and found 3G Internet access will be available in Turkey "later this year" (as of March), so an unlocked, 3G-capable phone or cellular hotspot would probably be your best bet for email access there. There are three vigorously competing GSM providers so it looks like service rates should be at least somewhat affordable. I know that 3G service in the Philippines last time I checked was still metered, not flat rate, but not too expensive if you were traveling as opposed to doing work that required Internet access. So again, Turkey might be similar, although that's just a guess. As I said in my previous message, you need GSM, which in the USA is either AT&T or T-Mobile.
If you knew Turkish, this web site might provide the information you need:
It certainly had some entertainment value even if I didn't understand a word! I'm pretty sure you need Flash to make any sense out of it, though.
This was the least difficult to understand of the three company pages - looks like this is the 3G page but the rates are still opaque to me :-(.
All Turkish cell providers are here:
GSM Coverage Maps | Turkey
Hope that helps.
It really is a pity INMARSAT is not a shade more reasonable with their pricing. I knew someone years back with a 120' motor yacht with it who said service was great, but I'm sure even he shuddered to pay his bill every month. If my memory serves, back then it was $12 per minute connected to the Internet, and speeds were only 56k!