If travelling to Korea to attend AOGS 2009, you may require a temporary VISA to enter the country.  Please visit Korean Immigration to find out if your country requires a VISA. 

Tourist & Business Visas
Visitors from countries not under Visa Exemption Agreements must apply for a visa extension if planning to stay for more than 30 days. Depending on the situation of the consulate, the visa extension will be issued 1 to 3 days from the day of application. Applicants require a completed application form, a recent passport-size colour photo and application fee. Visitors do not require the outbound flight ticket. Visa extensions are usually for 90 days.
All visas including long-term visas are for a single visit. Therefore anyone who wishes to leave the country and re-enter later on during the allowed period of stay should obtain the Re-entry Permit from the Ministry of Justice prior to departure. For business visas, the intention of activities must be clearly stated on the visa application form.

Visa application should be made at Korean Embassies or consulates abroad. It is required for the visa applicants to submit passport, application forms, a recent passport-style color photograph, and such other documents as determined by the status of stay.

1. Single entry visa for a stay of no more than 90 days : USD30
2. Single entry visa for a stay of more than 90 days : USD50
3. Multiple entry visa : USD80
4. Prolongation of Re-entry Permit : USD20

*For Citizens of United States of America, multiple entry visa fee is USD45
on the basis of   reciprocity since the mutual agreement in 1994.

Extensions for tourist visas are possible in special cases such as accidents, health problems, flight cancellation, etc. Applications for visa extensions can be made at a local immigration office at least one day before the day of expiration.

Ministry of Foreign Affairs and Trade: http://www.mofat.go.kr
Immigration Bureau: http://www.immigration.go.kr