Here are a few FTP software recommendations:
FILEZILLA: WINDOWS, MAC, LINUX
Very easy to use and supports FTPS (FTP over SSL, for encrypted, secure connections). MORE INFO
Here is an instructional video on YouTube that explains how to download, install and use FileZilla, to get you up and running in no time:
FIREFTP: WINDOWS, MAC, LINUX (requires Firefox)
This is a plug-in for Mozilla Firefox. We've not tried it yet, but a user reports it works well with our service. MORE INFO.
We are told this one is a great free FTP client for Apple Mac users. MORE INFO.
Also, there is a nifty FileManager built right into your cPanel, that you can use to upload and manage files on our server.
For information on SFTP (FTP via SSH), see THIS ARTICLE.