new YourTimer;
forward YourPublic();

if (strcmp("/bla", cmdtext, true, 9) == 0)
{
SendClientMessage(playerid, COLOR_WHITE, "*you must wait 60 seconds.. bla");
YourTimer = SetTimer("YourPublic", 3000, 0);
return 1;
}
public YourPublic()
{
KillTimer(YourTimer);
SendClientMessage(playerid, COLOR_WHITE, "*you have wait 60 seconds");
return 1;
}