I know of a few good ways to build web clients in PowerShell: the .NET classes System.Net.WebClient and System.Net.HttpWebRequest, or the COM object Msxml2.XMLHTTP. From what I
It looks very easy
$wc = New-Object NET.WebClient
$wc.DownloadString($url)
$wc.ResponseHeaders.Item("status")
You can find the other available Response Headers in the ResponseHeaders property (like content-type, content-length, x-powered-by and such), and retrieve any of them via the Item() method.
... but as rob mentions below, sadly, the status property is not available here