There are several (free) programs out there that will allow you to split a big file into emailable chunks, and then join them back together. I've used HJSplit, but other than "it works for me" I can't give a full recommndation.
Note that this is kind of a pain. You need to get the software, install it, etc. If you are going to be doing this often, it's worth it. Once you get the process set up, it's pretty easy. But if this is just a one or two time thing, I'd just burn a CD and mail it.