UploadFriendly
UploadFriendly is an easy to use Java Applet that will allow multiple file uploads on a web server in a web page. The control supports file filtering, limits and more. Samples available in the following languages: ASP, ASP.NET, PHP, Coldfusion and JSP
Link: http://www.uploadfriendly.com/
The standard upload control of HTML only allows you to pick one file. You can do multiple uploads using multiple file picker controls on the page, but it's not very easy to manage for the end user. The solution is to use a control client side to enable multiple file selection and upload. You can achieve this by using an ActiveX control or a Java applet. While ActiveX controls are fully integrated in windows, only the Java Applets are available on all platforms. This is why the best choice you could make is to select a cross browser system that will ensure that all your users will be able to use your applications.
Our applet can also be configured using a .NET control which makes things easier for the developer. However, you still can use the applet by using manual declaration in the page which makes it available for any web development languages.