Add an attachment to the SharePoint 2010 list item using web service in powershell

 
      ## Input Parameters required for attaching a file to the list item
      $uri="http://serverName:10736/sites/ECT/_vti_bin/Lists.asmx?wsdl"
      [string] $listItemId="3"
      [string] $listName="List"
      [string] $fPath = "D:\Lists.xml"    
      
      ## Check if the file exists in the path specified
      if([System.IO.File]::Exists($fPath))
      {
            ## Read the file
            $fStream=[System.IO.File]::OpenRead($fPath)
            [String] $fName=$fStream.Name
            [System.Byte[]]$bytes=New-Object -TypeName System.Byte[] -ArgumentList $fStream.Length
            $fStream.Read($bytes, 0, [int]$fStream.Length)
            $fStream.Close()
            
            ## Attach the file to the list item using web service
            $listWebServiceReference = New-WebServiceProxy -Uri $uri -UseDefaultCredential
            Write-Host -ForegroundColor Magenta "Adding the attachement to the list item........."
            $listWebServiceReference.AddAttachment($listName,$listItemId,$fName,$bytes)
            Write-Host -ForegroundColor Green $fName " is attached successfully to the list item"       
      }
      else
      {
            Write-Host -ForegroundColor Yellow "File does not exists in the specified path " $fPath
      }