There is no limit to the size of the file (MB) that can be attached and sent in an email. However the sending of mails with large file attachments is not recommended due to the fact that they may not be delivered to the intended recipient(s) as many mail networks will reject mails with a size in excess of 13-14MB.
To distribute large files to email recipients we recommend that large files are uploaded to your hosting account via FTP or File Manager and a link to these files is sent to recipients instead of an attached file. On receipt of your email recipients click the link(s) to access the file(s).
Other popular ways of distributing and sharing files online include www.dropbox.com, www.yousendit.com etc.