The program WinMx is legal. It allows computers to transfer data
to another computer. This, unsurprisingly, is legal.
Offering copyrighted material for others to download without
permission of the copyright holder is an infringement of copyright.
This is a separate thing from using WinMx, though you can use WinMx
to do this. You can also use email to do this. Or Windows Live
Messenger, etc. Or Bluetooth it from your phone to another phone.
Does this make mobile phones illegal? No.
Using a program to download and copy copyrighted material
without paying a royalty fee is illegal. It is stealing, plain
& simple. It's not always as illegal as some think. If you live
in Canada your Free and can use it without any worries. However
it's illegal in the USA and the UK. A kid in the UK was downloading
from a site. The father got fined. This was quite recent (2005). A
14 Year old girl in the UK downloaded 1400 music files. Her mother
faces fines of 5000 pounds.
Currently, WinMX does not work at all unless you apply certain
patches to get it to work. The RIAA had seized the domain and the
old cache servers no longer work. However, even after applying the
patches, you might not be able to find anything due to attacks on
the network. Someone found a vulnerability that will cause the hubs
to send you the results of nearly every file on the entire network,
thus rendering WinMX mostly useless.