Sending large files to people over email is not recommended, so the usual way to do it is FTP. This is fine if it's me a designer / developer but to get a non techy client to do it would be a mission indeed. The solution is a service like YouSendIt. Basically they make it really easy for people to send large files over the 'interweb' and it's free. There are loads of really cool features to if you are willing to pay and go pro.
Recently I had a client who wanted me to build them a large content managed video blog site for a very small price indeed. The solution was not to tell them to go elsewhere but to send them unedited video tutorials using YouSendIt, so now they can build the rest of the site and manage it themselves.
There's even a multitude of cross platform applications and plugins that let you send files even more easily. So it's bye bye FTP!

