There are a few different implementation of FTPS or FTP over SSH. The most common is to use the server's SSH port (typically port 23, which is more or less and encrypted version of the telnet port 21) to establish the control connection over which the FTP username and password, as well as the file commands, are transmitted. This method does not encrypt the actual files, only the commands, but the primary purpose is to keep the username and password secure. Wikipedia has an article about this subject with a good selection of links to software apps (FTP servers and clients) that support the various methods at
FTPS - Wikipedia, the free encyclopedia.
If your question was about using SSL/SSH to further secure WEP, I don't have a specific article, but I can give a very basic example. Most people know how to encode speech into pig latin - that is more or less a weak, easily broken cipher like WEP. Knowing how pig latin works, you can easily decode any message encoded in that way. However, if I am talking to someone in Spanish (think SSL or SSH) and then encoding it in pig latin, when you decode the pig latin, you are left with the Spanish conversation. If you don't know Spanish, you won't be able to understand the conversation despite having broken the first level of encryption.
Granted, WEP is used less and less, but people are rapidly finding ways of decoding wireless communications. SSL and SSH however have not yet been broken in any practical way.