To find out what FTP is, click here.
Whatever web browser you are using, is enough to browse FTP sites and get files. An ftp site's URL will look something like ftp://ftp.cdrom.com/pub/. Click on the link to get an example of an FTP site. You should see a list of files and/or directories. There are also a few reasons why you might not. Sometimes the more popular FTP sites are very busy and it mught take a while for a connection to open up for you.
Navigating FTP sites with your web browser is a lot like navigating web pages. Just click on the directory to view it's contents, or click on a file to download it to your computer.
For people who want to do more advanced file operation, click here to get a list of FTP client, download them, and view their help files on how to use them. With an FTP client, you can upload files, copy files, and more.