Updated README with usage examples.

README.md

@@ -1,2 +1,84 @@
 # sitemap-xml-php
-PHP library for writing sitemap XML.
+PHP library for writing sitemap XML conform with the [sitemaps.org schema](http://www.sitemaps.org/protocol.html).
+
+# Usage
+
+Note that the SiteMapXmlWriter classes will always write a new sitemap. It's not possible to edit or delete entries from an existing sitemap.
+
+## Urlset
+
+[http://www.sitemaps.org/protocol.html#urlsetdef](http://www.sitemaps.org/protocol.html#urlsetdef)
+
+**Example**
+
+	// Create a new urlset writer.
+	$writer = new SiteMapUrlSetXmlWriter();
+	$writer->open('your/path/to/file.xml');
+
+	// Create a new entry object.
+	$entryLocation = Url::fromNative('http://foo.bar/file.html');
+	$entryModified = Date::fromNative(2015-05-19);
+
+	$entry = new SiteMapXmlEntry($entryLocation);
+	$entry->setLastModified($entryModified);
+
+	// Write the entry object.
+	$writer->write($entry);
+
+	// Close the writer. (Will save the XML.)
+	$writer->close();
+
+**Result**
+
+	<?xml version="1.0" encoding="UTF-8"?>
+	<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
+	 <url>
+	  <loc>http://foo.bar/file.html</loc>
+	  <lastmod>2015-5-19</lastmod>
+	 </url>
+	</urlset>
+
+## Sitemap index
+
+[http://www.sitemaps.org/protocol.html#sitemapIndex_sitemap](http://www.sitemaps.org/protocol.html#sitemapIndex_sitemap)
+
+**Example**
+
+	// Create a new sitemap index writer.
+	$writer = new SiteMapIndexXmlWriter();
+	$writer->open('your/path/to/file.xml');
+
+	// Create a new entry object.
+	$entryLocation = Url::fromNative('http://foo.bar/sitemap-file.xml');
+	$entryModified = Date::fromNative(2015-05-19);
+
+	$entry = new SiteMapXmlEntry($entryLocation);
+	$entry->setLastModified($entryModified);
+
+	// Write the entry object.
+	$writer->write($entry);
+
+	// Close the writer. (Will save the XML.)
+	$writer->close();
+
+**Result**
+
+	<?xml version="1.0" encoding="UTF-8"?>
+	<sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
+	 <sitemap>
+	  <loc>http://foo.bar/sitemap-file.xml</loc>
+	  <lastmod>2015-5-19</lastmod>
+	 </sitemap>
+	</sitemapindex>
+
+## Writing XML to output / memory
+
+Passing `null`, or `php://output` to the `open()` method of any `SiteMapXmlWriter` object will write the XML to the output stream.
+
+Passing `php://memory` will write the XML to the memory stream. 
+
+
+
+
+
+