http://www.vsftpd.beasts.org The Very Secure FTP.
http://www.cert.org The Computer Emergency Response Team. The place to go to learn about current security holes, and the latest "virus alert" email.
http://www.openssh.org The open-source Secure Shell home. OpenSSH includes the Secure FTP client.
http://www.cert.org/tech_tips/anonymous_ftp_config.html Excellent guidelines for safely setting up an anonymous FTP server.
http://www.gftp.org The GNOME FTP client.
http://kbear.sourceforge.net A KDE-based FTP client.
http://www.ncftp.com/ncftp/doc Documentation for the NcFTP client and server.
http://wget.sunsite.dk Wget, the GNU tool for non-interactive (scripted) file transfer.
http://enterprise.linux.com/article.pl?sid=04/12/20/1910209 A pithy description of what you can do with wget.
http://www.gnutelliums.com/linux_unix A list of Unix/Linux Gnutella clients.
http://gtk-gnutella.sourceforge.net GTK-Gnutella.
http://bittorrent.com Bram Cohen's BitTorrent home page.
http://azureus.sourceforge.net Azureus, the Java BitTorrent client.
http://www.java.com/en/download Download the latest Java Runtime Environment here.
http://www.portforward.com/routers.htm Get help opening your hardware router for BitTorrent.
http://gift.sourceforge.net The GiFT open-source FastTrack peer-to-peer project.
http://apollon.sourceforge.net A GUI for GiFT.
http://kmldonkey.org KMLDonkey GUI client.
http://www.nongnu.org/mldonkey The home of MLDonkey, where you can download the core program. Front page links to all the file-sharing networks the client supports.
http://www.mldonkeyworld.com News, downloads, and support forums for all MLDonkey users.
http://wiki.etree.org/index.php?page=BitTorrent The eTree BitTorrent FAQ page, with much good information on BitTorrent clients, how BitTorrent works, and where to find content.