[Ghett0]

pawn Code:

public OnPlayerCommandText(playerid, cmdtext[])
{
    if((strcmp(cmdtext, "/an", true, 3) == 0) && IsPlayerAdmin(playerid))
    {
        strdel(cmdtext, 0, 4);
        GameTextForAll(cmdtext, 2000, 3);
        return 1;
    }
    return 0;
}

There. You'll have to be logged into rcon to use it.