Apple yesterday announced a new addition to MobileMe that will enable users of the service to share files with others via iDisk. The feature was actually promised back in July but got delayed for months due to the online service's rocky launch, which Steve Jobs himself described as "not up to Apple's standards." Anyway the feature is now live and gives MobileMe users an alternative to similar free and paid online services.
Apple has provided a video tutorial demonstrating the new file sharing feature, which basically involves selecting a file to share, and choosing one or more recipients for the automatically generated private URL pointing to that file - which can optionally be set to expire after a period of time. The service works much like YouSendIt, though rather than uploading a file, you point to an existing file on your iDisk. Conversely, another cross platform application called Dropbox allows you to easily upload files and assign them a public link, but offers no way to set expiration dates for the links yet.