[Dubya]

Alright... I haven't tested this, but it compiled fine.. So..

pawn Code:

new time = 60;
new timer1;

forward timer();
public timer()
{
    new string[128];
    if(time > 0)
    {
        time--;
        format(string, sizeof(string), "%d", time - 1);
    }
    else
    {
        time = 60;
        format(string, sizeof(string), "Go!");
        KillTimer(timer1);
    }
    GameTextForAll(string, 1000, 4);
    return 1;
}


CMD:countdown(playerid)
{
    timer1 = SetTimer("timer", 1000/* 1 second */, true);
    return 1;
}