system/classes/Db_MySQL.php
public function bindArray($param, $values, $type = null)
    {
      foreach ($values as $index => $value) {
        $this->bind($param.$index, $value, $type);
      }   
    }
public function bindArray($param, $values, $type = null)
    {
      foreach ($values as $index => $value) {
        $this->bind($param.$index, $value, $type);
      }   
    }
Iterates over an array binding each element.
Giving it ":id" for the param would result in the bindings of:
:id1,
:id2,
:id3, etc