public static extern uint WlanGetAvailableNetworkList(IntPtr hClientHandle, ref Guid pInterfaceGuid, uint dwFlags, IntPtr pReserved, ref IntPtr ppAvailableNetworkList);

     Public Shared Function WlanGetAvailableNetworkList(ByVal hClientHandle As IntPtr, ByRef pInterfaceGuid As Guid, ByVal dwFlags As UInteger, ByVal pReserved As IntPtr, ByRef ppAvailableNetworkList As IntPtr) As UInteger

WlanGetAvailableNetworkList(ClientHandle, ref pInterfaceGuid, WLAN_AVAILABLE_NETWORK_INCLUDE_ALL_MANUAL_HIDDEN_PROFILES, new  IntPtr(), ref  ppAvailableNetworkList);

This method just tells the interface to start doing a scan. If you want to get results as they come back, you have to register a callback function. An easier way is to call this method, wait a while, then use WlanGetAvailableNetworkList