Recently in P2P Category

Skype is free Internet telephony that just works
Tested this on Wndows, and Linux (Fedora Core 2) and must say I am suitably impressed. You can and should use some sort of quality headset to get the full benefit of VoIP telephony, I recommend something USB based and was pleased to find out that Logitech's gaming headset is USB based and works without any drivers on Windows 2000 and Linux Fedora Core 2!!!

Our software's quick and easy to get started with. Download, register, install, plug in your headset, speakers or USB phone and start calling your friends. The calls have excellent sound quality and are highly secure with end-to-end encryption. You don't even need to configure your firewall or router or any other networking gear. It just, you know works. [...] And it doesn’t just work on Windows, like some other software you may know. Skype is also for Mac OS X, Linux and PDAs using Pocket PC, with a native look and feel for each platform. Talking, sending instant messages or even file transfers work between different platforms like a charm.

update: this was a logitech usb ps2 Playstation 2 headset it seems to be discontinued now. and comments?

WINW
More on the P2P front. A complete rewrite and not compatible with the waste protocol. So not so much a fork but an improvisation around a theme.

WINW is a small worlds networking utility. It was inspired by WASTE, a P2P darknet product released by Nullsoft in May 2003 and then withdrawn a few days later. The WINW project has diverged from its original mission to create a clean-room WASTE clone. Today, the WINW feature set is different from that of WASTE, and its protocol is incompatible with WASTE's protocol. However, WINW and WASTE achieve similar goals: they allow people who trust each other to communicate securely.

MUTE
If the 21st century has taught us anything so far it is that centralized resources are extremely vulnerable and that decentralization and the edge of the network is where the value lies in communication and resources. Mute presupposes that the network is compromisable and institutes a method to preserve a free flow of commands and resources. I verified that this is a valid implementation of the peer to peer network model.

Following the death of Napster, all of the file sharing networks that rose to main-stream popularity were decentralized. The most popular networks include Gnutella (which powers Limewire, BearShare, and Morpheus) and FastTrack (which powers KaZaA and Grokster). The decentralization provides legal protection for the companies that distribute the software, since they do not have to run any component of the network themselves: once you get the software, you become part of the network, and the network could survive even if the parent company disappears.

File trading may fund terrorism
Many excerpts below. The MPAA wants to muddy the water and tar P2P with the same brush as organized mass duplication plants that are pirating works outside the country. See Cringely's How BayTSP is Enforcing the Digital Millennium where we learn of the company that is logging P2P transactions...
How Peer-to-Peer File Sharing Is Likely to Change Big Media which mentions Microsoft research on P2P.
The follow up: Reader Reflections on Peer-to-Peer and Big Media

But when subcommittee chairman Lamar Smith, a Texas Republican, asked Malcolm for examples of cases where file trading was connected to terrorism, Malcolm said he couldn't give concrete examples. "It would surprise me greatly if the number were not large," Malcolm added. "This is an easy enterprise to get into; the barriers of entry are very small, and the profits are huge."[...] Malcolm also called the creators of "warez" file-trading organized criminals, although he admitted warez fans aren't motivated by money. Many warez groups, who distribute pirated commercial software over the Internet, operate in a very organized fashion, Malcolm said, with a hierarchy based on how much individual members contribute to the group. Much of the pirated material on the Internet comes from warez groups, Malcolm suggested.[...] Jack Valenti, president and chief executive officer of the MPAA, described a couple examples of copying operations that had been raided outside the U.S. , and he said 26 copying factories in Russia can copy 300 million DVDs and CDs a year. He claimed his industry is losing billions of dollars a year to piracy, although a couple of representatives also pointed out the motion picture industry had record box-office receipts in 2002.