There are all sorts of tools to convert between one format to another, and all sorts of tools for downloading flash video from specific sites.
But if the video is streamed, and has DRM then most of the tools won't work.
I'm not going to keep guessing at what kind of technology you are talking about, so if you are specific (e.g. progressive http downloads of flv video) I can try to find something for you, otherwise just try searching for what you want specifically (e.g. "download video from x.com" using the actual site domain and all).