ed2k is the most effective way to share many rare files even if each file is downloaded once in a lifetime. Although you can download all files directly from site or sometimes with torrent, we recommend to use eMule for sharing virtual images from OSVirtual. We use this eMule server.
OSVirtual has used Rapidshare and similar services; but they sometimes die. And eMule always works. Using own hosting is expensive for OSVirtual's traffic. And eMule is free.