This Cotonti plugin lists all siblings of a page and allows easy navigation to previous/next page.
<!-- BEGIN: SIBLINGS -->
<ul id="siblings">
<!-- BEGIN: SIBLING -->
<li class="{PAGE_SIBLING_ODDEVEN}">
<a href="{PAGE_SIBLING_URL}"<!-- IF {PAGE_SIBLING_ISCURRENT} --> style="font-weight:bold;"<!-- ENDIF -->>{PAGE_SIBLING_NUM}. {PAGE_SIBLING_TITLE} ({PAGE_SIBLING_AUTHOR})</a>
</li>
<!-- END: SIBLING -->
</ul>
<!-- END: SIBLINGS -->