Powershell script add webpart to your Sharepoint 2010 sites in your site collection

$site = new-object Microsoft.sharePoint.SPSite("http://yoursite.com/")
$web=$site.OpenWeb()$pubweb = [Microsoft.SharePoint.Publishing.PublishingWeb]::GetPublishingWeb($web)$defaultpage=$pubweb.GetPublishingPages()[$pubweb.DefaultPage]$defaultpage.CheckOut()$webpartmanager=$web.GetLimitedWebPartManager($defaultpage.Url,
[System.Web.UI.WebControls.WebParts.PersonalizationScope]::Shared)$webpart=new-object  Microsoft.SharePoint.WebPartPages.ContentEditorWebPart
$webpart.ChromeType=[System.Web.UI.WebControls.WebParts.PartChromeType]::TitleOnly;
$webpart.Title="Name of your Webpart"
$webpartmanager.AddWebPart($webpart, "Left", 0);$defaultpage.CheckIn("Checked in Webpart")
$defaultpage.listItem.File.Publish("Published Webpart")
if ($defaultpage.listItem.ParentList.EnableModeration)
{
   $modInformation = $defaultpage.listItem.ModerationInformation   if($modInformation.Status -ne [Microsoft.SharePoint.SPModerationStatusType]::Approved)
   {
      $defaultpage.ListItem.File.Approve("Approved Page")
   }
}