MobileMe owners to share files on iDisk
iDisk is a free app that allows users registered with MobileMe to browse and share files on their iPhone and iPod touch devices over the Internet. The list of permitted files includes presentations, Microsoft Office and PDF documents. All you need to do to browse the available files is select them and once you decide to share any of them, you will have to choose who they will be visible to (again users with access to MobileMe). The chosen users will be then sent an email link to download the content. The maximum file size is limited to 20MB.
source: Apple
source: Apple
Things that are NOT allowed: