Since the early days of jailbreaking the apps that allow the iPhone to be a web or file host has been popular, and this app gives you that, and access to your iDisk, for free. This is the free, ad-supported sibling to Discover Pro, and offers the user WebDAV sharing with optional user permissions and password protection. Without doing any configuration you can use a WebDAV client (Mac OS X Finder, many Linux distributions’ file manager, Transmit, etc…). Users of this app which are connected to the same WiFi network are able to share files and this app is also a client to MobileMe’s iDisk or the Discover Server, a free Windows/Mac download from the developer’s website (which is currently inaccessible as of writing this). [For clarification, this app will work with or without internet access, however you can only share files when it is connected to WiFi.]
You can get this app for free in the App Store.