CMD:pm(playerid, params[])
{
    new str[256], str2[256], id, Name1[MAX_PLAYER_NAME], Name2[MAX_PLAYER_NAME];
    if(sscanf(params, "us", id, str2))
    {
        SendClientMessage(playerid, 0xFF0000FF, "Usage: /pm <id> <message>");
        return 1;
    }
    if(!IsPlayerConnected(id)) return SendClientMessage(playerid, 0xFF0000FF, "ERROR: Player not connected");
    if(playerid == id) return SendClientMessage(playerid, 0xFF0000FF, "ERROR: You cannot pm yourself!")
    GetPlayerName(playerid, Name1, sizeof(Name1));
    GetPlayerName(id, Name2, sizeof(Name2));
    format(str, sizeof(str), "PM To %s(ID %d): %s", Name2, id, str2);
    SendClientMessage(playerid, 0xFF0000FF, str);
    format(str, sizeof(str), "PM From %s(ID %d): %s", Name1, playerid, str2);
    SendClientMessage(id, 0xFF0000FF, str);
    return 1;
}

if(playerid == id) return SendClientMessage(playerid, 0xFF0000FF, "ERROR: You cannot pm yourself!");