YouTube Download Web Service: Integrate YouTube Download into your .NET apps FREE
Here is an interesting web service that allows applications to download youtube videos. Applications that require interaction with youtube can obviously use the YouTube API's to provide exhaustive youtube functionality right from their web sites. However, the only API function that is missed is the ability to download from Youtube.
The Youtube web service provides this missing functionality.
The service is located at http://www.ecubicle.net/youtubedownloader.asmx
What the service does is provide the download URL for any video on Youtube. .NET applications can then use any method to access the download URL and download the file. For example, WebClient.DownloadFile() method can be used to download the file directly if the returned URL is passed to DownloadFile.