You could use the following XSLT to create a sitemap

<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet
	version="1.0"
	xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
	xmlns:msxml="urn:schemas-microsoft-com:xslt"
	xmlns:umbraco.library="urn:umbraco.library"
	exclude-result-prefixes="msxml umbraco.library">

	<xsl:output method="html"/>

	<xsl:param name="currentPage"/>
	<xsl:variable name="maxLevelForSitemap" select="6"/>
	
	<xsl:template match="/">
		<div id="sitemap">
			<xsl:call-template name="drawNodes">
				<xsl:with-param name="parent" select="$currentPage/ancestor-or-self::node [@level=1]"/>
			</xsl:call-template>
		</div>
	</xsl:template>

	<xsl:template name="drawNodes">
		<xsl:param name="parent"/>
		<ul>
			<xsl:for-each select="$parent/node">
				<li>
					<a href="{umbraco.library:NiceUrl(@id)}">
						<xsl:value-of select="@nodeName"/>
					</a>
					<xsl:call-template name="drawNodes">
						<xsl:with-param name="parent" select="."/>
					</xsl:call-template>
				</li>
			</xsl:for-each>
		</ul>
	</xsl:template>
</xsl:stylesheet>