NuParadigm DrizzleCast is a podcast client for Windows that uses Microsoft BITS (Background Intelligent Transfer Service) technology to download podcasts and general RSS enclosures on Windows XP OSes. BITS also known by it's codename "Drizzle",  is a lesser-known technology that enables you to use idle bandwidth to manage the download of content.  It's a good start and a great application of of the BITS platform. Read more and view screenshots over at The Green Button.