hi, i still dilli delli on which phone provider i should use at korea.
anyway found out a new infor..hehe dunno here got stated b4 or not. but just provide to u all for extra infor :-
http://asiaenglish.visitkorea.or.kr/ena/AK/AK_EN_1_5_7.jspbeside "rent a phone" service, u can purchase a sim card also. no identity card needed.
i email to kimjin@simcardkorea.com to enquiry tis morning, & by afternoon got a reply jor. here is the extract infor :-
<Rent a Prepaid SIM from "SIMCARD KOREA">-Rental fee: 19,800won
-Korea Local outgoing call: 390won/min.
-Korea International Outgoing call to Malaysia: 390won/min.
-Incoming Call: Free
※Deposit 20,000 won, but it would be refunded when you returned the SIM
<Buy a Prepaid SIM from "SIMCARD KOREA">-59,000won
-10euro initial airtime is included
-Korea Local outgoing call: 270won/min.
-Korea International Outgoing call to Malaysia: 270won/min.
-Incoming Call: Free
※Our SIMcard is kind a Roaming SIM, it works in 166countries without any other registration or activation process.
The rate price is quite cheaper than any other service.
(to the 55countries, the intl call rate is same as Local: 270won/min. only)
Phone> A) iPhone4 : Need to Cut and Sync with iTunes.
a. Visit our partner store(Location: 1F, Incheon Korea International Ariport)
=> more informations plz look "5)" this below.
b. Ply Buy SIMCARDKOREA's Global Tech SIMCard, or Just "SIMCARDKOREA!" is enough!
c. On that store, we are preparing Micro SIM Cutter for our customers, Freely use it

(Insert the SIM as follow the Marks on the cutter > Cut the SIM > Insert the SIM > Power the phone on
> Enter PIN(4digits: printed on the SIM) > Sync with iTunes through a Computer(plz ask the staff again)
d. Now, all Ready to use

B) iPhone3 : Need to Sync with iTunes.
C) BlackBerry : 3G/GPRS data is Not available
D) MotoGlam : May not Available(by the phone own software problem: Unlocked & Upgrade needed)
E) Others : Have to sure it's Unlocked 3G, that's enough.
3) Can i surf internet using this Prepaid SIM Card ?(3G/GPRS DATA: for "BUY"SIM User only)=> This is prepaid SIMCARD, but we are providing DATA service, also
Wifi is Free, but you need to use 3G(GPRS) Data: it start from 1Euro/100KB (The rate is different as the countries where you are in and in korea it's 3Euro/100KB) To use 3G data you have to keep the call balance over 50 euros.
(plz see the manual included: we are providing Korean/ Enlish manual both)
but..just..If your phone support wifi function and if there's any limits to use, it's free.
and Usually in korea using wifi data service is really easy (coffee shops, fast food restaurant, and lots spots support wifi)