I only used ftp_get a few times, but it works something like this.
$host = "ftp.suse.de";
//conect to host
$ftp = ftp_connect("$host") or die ("Unable to connect");
//must login even if anonymous
ftp_login($ftp, "username","password") or die ("Login Failed");
//get file
ftp_get($ftp,"/yourdir/yourfile.zip","/i386/somefile.zip",FTP_ASCII);
//close
ftp_quit($ftp);
Hopefully that helps some.
Rodney