EAUpload
EAUpload is an ASP.NET file upload component that provides expansive functionality for ASP.NET applications to work with uploaded files to the web server by a browser. It conforms to the specification that is defined in RFC 1867 (Form-based File Upload). EAUpload doesn't require any client side control such as ActiveX or Java applet, but if you use any client side control then EAUpload can still operate with file which was uploaded by these controls. Uploaded files are buffered to disk. It protects a web server from a memory leakage. EAUpload also includes a simple way to guard against denial of service attacks. It provides a possibility to limit the size of the files which can be uploaded to the web server. Installation package includes many example written on C# and VB.NET, it contains also an advanced example of Ajax File Upload.