string xml = "<?xml version=\"1.0\" encoding=\"utf-8\"?><tags><tag tagnumber=\"1\"><epc>038604c02010460000394bc9</epc><time>2012-6-26 10:56:42 +08:00</time></tag><tag tagnumber=\"2\"><epc>038604c02010460000394bbe</epc><time>2012-6-26 10:56:42 +08:00</time></tag><tag tagnumber=\"3\"><epc>038604c02010460000394bc6</epc><time>2012-6-26 10:56:42 +08:00</time></tag></tags>";
XmlDocument xmlDoc = new XmlDocument();
xmlDoc.LoadXml(xml);
XmlNodeList list = xmlDoc.SelectNodes("tags/tag");

DateTime[] array = new DateTime[list.Count];
for (int i = 0; i < list.Count; i++)
{
    array[i] = DateTime.Parse(list[i].SelectSingleNode("time").InnerText);
}