Here is a solution but obviously I don't know the full xml source:
Code:
<root>
<categories>
<cat>car</cat>
<cat>truck</cat>
</categories>
<record>
<name>mmm</name>
<nameCat>car</nameCat>
</record>
</root>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="/">
<html>
<head><title>Drop Down</title></head>
<body>
<select id="lstCategories">
<xsl:apply-templates select="root/categories/cat"/>
</select>
</body>
</html>
</xsl:template>
<xsl:template match="categories/cat">
<xsl:variable name="currentValue" select="text()"/>
<option value="{$currentValue}">
<xsl:if test="//record/nameCat[ . = $currentValue]">
<xsl:attribute name="selected">selected</xsl:attribute>
</xsl:if>
<xsl:value-of select="$currentValue"/>
</option>
</xsl:template>
</xsl:stylesheet>
Joe (MVP - xml)