I used this one today to download all images of a Picasa album:
$feed=[xml](New-Object System.Net.WebClient).DownloadString("http://the/rss/feed/url")
foreach($i in $feed.rss.channel.item) {
$url = New-Object System.Uri($i.enclosure.url)
$url.ToString()
$url.Segments[-1]
(New-Object System.Net.WebClient).DownloadFile($url, $url.Segments[-1])
}