If you’ve ever tried to email a very large file you may have noticed there’s a limit of about 10MB on email attachments. Here’s a super easy way to send a large file to someone else using OSX Mountain Lion or later.
iDisk was Apple’s online disk space that you get automatically if you sign up for MobileMe. It has been discontinued. The easiest replacement is probably dropbox. (Note: there’s now a better way using Apple Message that I describe here.)