new jailtime[MAX_PLAYERS];

// OnGameModeInit
SetTimer("unjail",1000,1);

// OnPlayerConnect
jailtime[playerid] = 0; // so new players dont get released after a while :P only coz the before player was in jail ^^

// jail
SetPlayerPos(playerid,...);
SetPlayerInterior(playerid,...);
jailtime[playerid] = 60;

public unjail() {
  for(new i = 0; i < MAX_PLAYERS; i++) {
    if(IsPlayerConnected(i)) {
      if(jailtime[i] > 0) {
        jailtime[i]--;
      } else if(jailtime[i] == 0) {
        jailtime[i]--;
        SetPlayerPos(i,...);
        SetPlayerInterior(i,...)
      }
    }
  }
}