One of the ISVs I work with is Memba. Memba last year started to beta a file transfer platform to publish, share, send and transfer very large files over the Internet - Velodoc.
From that work they went on to create Velodoc XP Edition, a downgraded version of Velodoc without repository and without security which they recently released under the GPL license at http://www.codeplex.com/VelodocXP.
This is a comprehensive package containing: 1. An ASP.NET Http module to stream the upload of large files (compatible with IIS7 integrated pipeline mode); 2. An ASP.NET Http handler to provide resumable downloads of large files; 3. ASP.NET server controls to develop user interfaces with file upload functionality, including a multi-upload control, a listview control and a progress bar control; 4. A web application which is an FTP replacement for exchanging large files with email contacts and which also serves as a sample implementation of the components listed above; 5. A windows service to periodically purge old files; 6. A test project; 7. A deployment project; 8. A setup project; 9. Documentation.
Also check out the following articles on codeproject.com:
Well done folks!!!