I have been working on a project that requires files to be uploaded to a Web server. No big deal... ordinarily. However this project is .Net. As a result the most obvious and simple implementation requires the entire contents of the file to be moved into memory. This is due to the architecture of IIS. IIS 6.0 deals with this a little better when run in isolation mode. However, this also has implication.
I found some good writings on this topic. It would seem that MS dealt with the download issue, but not upload. In any case the following presents a good overview of the issue. The upload issue is a tougher one to deal with. All of the implemented solutions I found use an ISAPI filter or something at that level in the architecture. Any way here are the links:
A nice overview of the problem (from the download perspective) here:
A good discussion of the upload issues (with solutions) here:
I snipped a bit of VB code from coderage at the asp.net forum available after the jump