[VonLeeuwen]

Wow, you are impatient.. Nope sorry can't help you.. Well, maybe I can :O

Code:

stock GetPlayerSpeed(playerid) // bottom of your script
{
    new Float:X, Float:Y, Float:Z;
    if(IsPlayerInAnyVehicle(playerid))
    {
        GetVehicleVelocity(GetPlayerVehicleID(playerid), X, Y, Z);
        return floatround(floatmul(floatmul(floatsqroot(floatpower(floatabs(X), 2) + floatpower(floatabs(Y), 2) + floatpower(floatabs(Z), 2)), 100), 1.621371192), floatround_round);
    }
    else
    {
        GetPlayerVelocity(playerid, X, Y, Z);
        return floatround(floatmul(floatmul(floatsqroot(floatpower(floatabs(X), 2) + floatpower(floatabs(Y), 2) + floatpower(floatabs(Z), 2)), 100), 1.621371192), floatround_round);
    }
}

You can add this somewhere, at a command or something, I'm sure you understand this

Code:

new Str[128];
format(Str, sizeof(Str), "You are driving %d km/hour!", GetPlayerSpeed(playerid));
SendClientMessage(playerid, Str);
return 1;

THIS IS NOT MADE BY ME, AND I DIDN'T TEST IT! IT HAS BEEN MADE BY "WANTED".