Setting up Vkontakte application to interact with

You must register on http://vkontakte.ru and add a new application. You will then receive an application id (api_id), which you will use in your VACs.

To use the desktop API type, the Vkontakte application type must be Desktop App.

You then have to acquire sid, mid and secret for a session by submitting your user credentials here: http://vkontakte.ru/login.php?app=@api_id&layout=popup&type=browser&settings=@permission_bit_mask

Note that sid is bound to IP from which it was acquired, so the authentication workflow should be integrated into your application.