How to share documents using Internet in a safe and secure way

Email the file to the other user.

This may seem the most simple method, but Google and Microsoft have enormous amounts of money spent on the security of their email systems (Gmail and Hotmail)

Use a secure, server based method using FTP

FTP stands for File Transfer Protocol, and its the system used to transfer websites onto the internet. If you upload it to an FTP server, the receiving person can be forced to use a username and password in order to download the file.

Use a file hosting service.

This may seem the most obvious, but it still is one of the easiest ways to transfer a file. Some services even allow you to set passwords on your files.

Examples: www.megaupload.com

www.rapidshare.com / www.rapidshare.de

www.sendspace.com

Thanks for reading :)