We recommend that delegates make visa applications in person one month before you proceed to Turkey to avoid any inconvenience on arrival. Visa regulations vary from country to country.
Please check the link below to establish the requirements for your country
http://www.mfa.gov.tr/visa-information-for-foreigners.en.mfa
Alternatively, to view the Visa fees at border gates, please click here - http://www.mfa.gov.tr/visa-fees-at-border-gates-for-2010.en.mfa