My advice:
1) BulletProof FTP Server: easy to configure and perfect for new/medium user. Get it
here
2) RaidenFTPD: perfect for advanced users, with many available scripts, functions and options. Get it
here
Be sure to read all the installation and setup manuals for those programs and if you have any question try emailing BulletProof FTP Server & RaidenFTPD support (with last one you can try it forum).