One of the best free FTP programs I have ever used is FileZilla. This is an open source software that has all the bells and whistles of well known premium FTP Clients. FileZilla is available in variety of formats so you can install it on Windows XP and Linux.
It’s current stable version is 2.2.29. Besides being a superb ftp client, FileZilla also has its own ftp server software. It’s also open source and free to download. I haven’t try its FileZilla server yet but I heard good things about it. Overall score I rate FileZilla a 8 out of 10 and 10 being the best free ftp software.