The best PC FTP program is probably WS_FTP. You can find the nearest place to download it for your version of Windows at www.shareware.com. In addition some versions of Windows 95 provide a basic FTP program. (You can locate it by using 'Find' or try typing 'FTP' in the 'Run...' window.)
The best Macintosh FTP program could be one of two: Fetch or Anarchie. Anarchie takes a little more effort to get working properly, but provides the most features and the nicest interface. Find the nearest place to download them at www.shareware.com.
UNIX has a built-in FTP program so that shouldn't be a problem if you are using Linux.