string newsName = "My first news";

// create tree provider instance

CMS.TreeEngine.TreeProvider provider = new CMS.TreeEngine.TreeProvider(CMS.CMSHelper.CMSContext.CurrentUser);

// get parent node for new document

CMS.TreeEngine.TreeNode parent = provider.SelectSingleNode(CMS.CMSHelper.CMSContext.CurrentSiteName, "/News", "en-us");

// create a new tree node

CMS.TreeEngine.TreeNode node = new TreeNode("cms.news", provider);

if (parent != null)

{

  // set document properties

  node.NodeName = newsName;

  node.NodeAlias = newsName;

  node.SetValue("DocumentCulture", "en-us");

  node.SetValue("NewsTitle", newsName);

  node.SetValue("NewsSummary", "Some summary.");

  node.SetValue("NewsText", "Some text.");

  node.SetValue("NewsReleaseDate", DateTime.Now);

  // create New document

  node.Insert(parent.NodeID);

}