private var playerCount : int = 0;

function OnPlayerConnected(player: NetworkPlayer) {
    Debug.Log("Player " + playerCount + 
              " connected from " + player.ipAddress + 
              ":" + player.port);
    // Populate a data structure with player information ...
}

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
    private int playerCount = 0;
    void OnPlayerConnected(NetworkPlayer player) {
        Debug.Log("Player " + playerCount + " connected from " + player.ipAddress + ":" + player.port);
    }
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

    private playerCount as int = 0

    def OnPlayerConnected(player as NetworkPlayer):
        Debug.Log(((((('Player ' + playerCount) + ' connected from ') + player.ipAddress) + ':') + player.port))