[Galaxy S I9000 General] alovell83:
Before reading this novel, me attempting to help, please note I don't know too much about cellular frequencies. I know a bit about American ones, which are amongst the most complicated and proprietary. I don't know much about Korean ones besides they are CDMA, which doesn't bode well for you. However, I believe I'm supposed to be able to travel with this phone and get data, so read on if you like to have a few options to test out. I can place a call to SK soon to find out more concrete info.

Did you pay the full, unlocked price? I think Precious new above seems to give compelling evidence that it isn't carrier locked, at least outside of Korea. However, perhaps you got a contract he didn't? If that's the case, look into getting the unlock code, it's super-simple.

Regardless, I'd assume it's the carrier frequency/network type isn't compatible. I believe this a "world phone" due to certain, vague comment I've read but I haven't specifically found out the exact frequencies utilized and for what purposes. Also, try to play with the wireless and network settings. Go to settings > wireless & network > mobile network settings > access point names > look to see if something with SK telecom is being utilized, this will probably create a conflict, update to something better if available, if not search on how to manually update APN

If that leads somewhere, but doesn't provide an instant fix, in the meantime you can try 2G networks, go back one step. wireless & network? mobile network settings> Use only 2G networks (better than nothing). Regardless of if it works, disable the function and then try to look further in this area depending on your firmware. I used to have a setting, I can't find it now so it might've been disabled and even useless when available, but I used to be able to select the type of network I want to connect to (e.g. 3G only, WCDMA only, best available, etc. I know this available on some international firmwares). Depending on the radio chip in the phone, this can be quite helpful if a network type your sim will provide data on is disabled that you can enable.

Another alternative, if you can make a carrier switch, try to find out the frequencies your carrier uses, then try to find out if any other frequencies are utilized in your area, then find out if any other carriers are available that utilize a different frequency and see if you can buy a prepaid sim or test a sim in their store to see if you can get data. I think this kind of case, where one carrier uses frequency X another Y, is almost solely found in the U.S., but it's worth a shot if it doesn't take much searching and/or all else fails.

It might take some playing around, but there should be hope of getting data as long as there is some form of compatible frequency that your carrier has that this phone utilizes. I don't have enough info on the chip to provide anything specific, hopefully in the near future I can gather that, perhaps I can call SK tomorrow.

One note...SK specifically doesn't do data over its 2G CDMA network, hopefully yours does in case that's compatible with the device. I have a decent feeling about the 2G having more available frequencies available to it, but that's a bit of speculation based on various other models and not necessarily applicable here.