File Access Strategy in a Multi-Threaded Environment (Web App)

I have a file which is an XML representation of some data that is taken from a Web service and cached locally within a Web Application. The idea being is that this data is very static, but just might change. So I have set it up to cache to a file, and stuck a monitor against it to check if it has been deleted. Once deleted, the file will be refreshed from its source and rebuilt.

WebDev: What is the best way to do a multi-file upload?

I want (barely computer literate) people to easily submit a large number of files (pictures) through my web application. Is there a simple, robust, free/cheap, widely used, standard tool/component (Flash or .NET – sorry no java runtime on the browser) that allows a web user to select a folder or a bunch of files on their computer and upload them?

How to Apply OpenFileDialog Function to a WebApplication

I am devoloping a Web Application, in which one Page has some neccessity that User should select any folder in the System and for ex if he selects ex:D:xyz, then this Path should be Saved in Database, I have written the Code for Storing in to Database and Remaining Every thing. But actually i think that if it is like a Browse Button click function to select the Folder, what i have made is, as i dont know how to make it in Web Application simply i used a textbox to be able to user to type the Path. Can, any one help me how to apply the Open File Dialog Functionality in a Web Page?