XML sitemap for Umbraco 7 (based on Cultiv Search Engine Sitemap package). See http://www.alexlindgren.com/archive/dynamically-generated-xml-sitemaps-with-umbraco-7/

XMLSitemap.cshtml

@inherits Umbraco.Web.Mvc.UmbracoTemplatePage
@using System.Linq;
@{
    Layout = null;
    Response.ContentType = "text/xml";
}<?xml version='1.0' encoding='UTF-8' ?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://www.sitemaps.org/schemas/sitemap/0.9 http://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd">
    @ListChildNodes(Umbraco.TypedContent(UmbracoContext.Current.PageId).AncestorOrSelf(1))
</urlset>

@helper ListChildNodes(IPublishedContent startNode)
{

    foreach (var node in startNode.Children.Where("hideInXmlSitemap == false"))
    {
        if (node.TemplateId > 0)
        {
            <url>
                <loc>@GetUrlWithDomainPrefix(node.Url)</loc>
                <lastmod>@(string.Format("{0:s}+00:00", node.UpdateDate))</lastmod>
            </url>
        }

        if (node.Level <= 100 && node.Children.Count() > 0)
        {
            @ListChildNodes(node)
        }
    }
}

@functions {
    private static string GetUrlWithDomainPrefix(string url)
    {
        if (url.StartsWith("/"))
            url = url.Substring(1);

        var domainPrefix = string.Format("http://{0}/", HttpContext.Current.Request.ServerVariables["HTTP_HOST"]);

        if (url.StartsWith(domainPrefix))
            return url;
        else
            return domainPrefix + url;
    }
}

shouldn't be there also a record for the root site before
@ListChildNodes(Umbraco.TypedContent(UmbracoContext.Current.PageId).AncestorOrSelf(1)) ?

right now it's starting from first child of the root, skipping the root itself