How to get app id and app secret:
Any kind of naver login related resource is available from this page http://developer.naver.com/wiki/pages/OpenAPI
For naver login specific documenation is here http://developer.naver.com/wiki/pages/NaverLogin
At first register your app from here http://developer.naver.com/openapi/register.nhn
After registration the most important part is to set the siteurl and callback url