Most ISP mailservers will stop a file that big - they usually set limits that are around 7Mb, or sometimes a little larger.
The way to send really big files is to use one of the transfer services like click here
It works like this:
1. You upload the file to the company's server, and include the address of the person you're sending to.
2. The company emails your recipient, telling him/her a file is waiting.
3. Your addressee goes to the site and downloads the file from the server.