Display entries including all locales for XML sitemap
Not sure, but I think the only way is to query for each locale and merge.

{% set siteLocales = craft.i18n.getSiteLocales %}
{% set pages = [] %}
{% for locale in siteLocales %}
    {% set localePages = craft.entries.section('pages').locale(locale.getId).find() %}
    {% set pages = pages|merge(localePages) %}
{% endfor %}

{% for page in pages %}
    {{ page.title}}
{% endfor %}