MCForge Plugin API 3.0

public override void Load(bool startup)
{
    OnPlayerConnectEvent.Register(temp, Priority.Normal, this);
}
public void temp(Player p)
{
    //code here
}

or

public override void Load(bool startup)
{

    OnPlayerConnectEvent.Register(delegate
    {
        //code here
    }, Priority.Normal, this);
}