FTP software is used for uploading and downloading files from your account. You don't have to use FTP software as your Domain Registration Services web hosting account control interface includes a file management feature; but managing your file base via FTP is a much quicker option. Most FTP programs also provide more powerful features, allowing you great control over your file base.

If you have used FTP applications in the past and haven't been impressed with their functionality or user interfaces, things have changed greatly over the years. Today's FTP software applications are very easy to use. One of the most popular FTP applications is FileZilla.

Among FileZilla's many features:

• Intuitive graphical user interface.
• Supports FTP, FTP over SSL/TLS (FTPS) and SSH File Transfer Protocol (SFTP)
• Versions available for Windows Mac OS X and more
• Supports resume and transfer of large files 
• Filename filters
• Directory comparison
• Remote file search
• Drag and drop support
• Remote file search - very handy if you have a large site

Another great aspect about FileZilla is that it's totally free.  You can download FileZilla here.

Other popular FTP programs you may wish to try:

BulletProof FTP
Ipswitch's WS_FTP Pro
Junod's WS_FTP LE
GlobalSCAPE's CuteFTP