sorry man, I edited my post to make it clear that DTA is a Firefox extension that works on any OS. :)
however, it's good to have clients on Windows, because you want people on there to be able to get your ISOs as easy as possible to install them, don't you? for that, there are 9 metalink clients.
here are the other Linux clients: aria2, KGet (KDE4 version), Phex, wxDownload Fast.