Server mod:How to activate a method when players connect or disconnect? [SOLVED]

I'm making a server mod and would like the mod to give a message to the player on login.

I figured out how to give a message when the player breaks a block or types a command, but still need to know how the mod can notice when a player logs in.

[SOLVED]

I made a new class

package my_package;

import net.minecraft.src.EntityPlayer;
import cpw.mods.fml.common.IPlayerTracker;

public class PlayerTracker implements IPlayerTracker
{

@Override
public void onPlayerLogin(EntityPlayer player)
{
	player.sendChatToPlayer("You just connected to this server.");
}

@Override
public void onPlayerLogout(EntityPlayer player)
{
	MyMod.playerLogout(player.getCommandSenderName() );
}


@Override
public void onPlayerChangedDimension(EntityPlayer player)
{
	// TODO Auto-generated method stub
}

@Override
public void onPlayerRespawn(EntityPlayer player)
{
	// TODO Auto-generated method stub
}
}

And in the class MyMod

	@Init
public void init(FMLInitializationEvent event)
{
	GameRegistry.registerPlayerTracker(new PlayerTracker());
}