How can I email a large keynote file?

I highly recommend the super-excellent and free DropBox (www.dropbox.com) - it integrates with the Finder and is super-simple to use. I collaborate with others daily using it - it's been a lifesaver.

I like DropBox and Google Docs and use both extensively, so it was a surprise to me that after a lot of trial and error I found iWorks is a better solution for certain situations. DropBox and Gdocs work best when sharing with people familiar with those systems. Ongoing work with collabators for example. On the other hand, iWorks is better for sending a file to someone you don’t know their workflow or tools. For instance, sending a presentation to a conference planner with whom you haven't worked before.

I prefer to use the Share > Share via iWorks for large files.The service is free and works great. I also use it to back up presentations when I am presenting out of town.

It's too large to email (from most public providers) Nealf's solution will work and there are many others, Google 'Share Files'