API page: http://api.drupal.org/api/drupal/includes!entity.inc/function/EntityFieldQuery%3A%3AfieldCondition/7
Minor change, but considering nearly all of the comments provide examples using arrays for the $value parameter, I propose that the doc be changed from:
$value: The value to test the column value against.
to:
$value: The value to test the column value against. Can be a string or an array of strings.