GNUnet is a peer-to-peer framework with focus on providing security. All peer-to-peer messages in the network are confidential and authenticated. The framework provides a transport abstraction layer and can currently encapsulate the network traffic in UDP, TCP, HTTP, HTTPS, or direct 802.11 (WLAN). GNUnet supports accounting to provide contributing nodes with better service. The services built on top of the framework include anonymous file sharing and a virtual network providing IPv4-IPv6 transition via protocol translation over the P2P network.
mod_musicindex is an Apache module aimed at being a C alternative to the Perl module Apache::MP3. It allows nice displaying of directories containing MP3, Ogg Vorbis, FLAC, or MP4/AAC files, including sorting them on various fields, streaming/downloading them, constructing playlists, and searching. It also provides features such as RSS and Podcast feeds, multiple CSS support, and archive downloads.
MLdonkey is a multi-platform, multi-network peer-to-peer client. It supports several large networks such as eDonkey, Overnet, Kademlia, Bittorrent, Gnutella (Bearshare, Limewire, etc.), Gnutella2 (Shareaza), or Fasttrack (Kazaa, Imesh, Grobster). Networks can be enabled or disabled. Searches are performed in parallel on all enabled networks. For some networks, each file can be downloaded from multiple clients concurrently.
Soulseek (http://www.slsknet.org) is a communication and file-sharing system. It is quite similar to Napster: it lets you exchange files, search for files, chat with other users in public and in private, browse their files, and get recommendations for music. SoulSeek for Linux is a GUI client for the system written in Python/wxPython. It includes all the major functionality: chat, searches, and file transfers.
aMule is short for "all-platform eMule-like file-sharing program", or, in short, "all-platform Mule". It's a port of the well-known eMule P2P client for the eDonkey2000 and Kad file sharing networks, supporting most of eMule's features. Additionally, it provides a small separate Web server and command line interface to connect to a running aMule via the network.
Sharity mounts shares exported by Windows, Samba, and other SMB/CIFS servers in the file system of Unix computers. It implements Resource Browsing, which is similar to the Windows Network Neighborhood (Netbios Workgroups and Active Directory), NTLM, NTLMv2, and Kerberos authentication, Microsoft's Distributed File System (DFS), and manipulation of Access Control Lists (ACLs).