You should go with LimeWire. I copied the following from the LimeWire website:

What is LimeWire?

The Most Sophisticated Filesharing Application
LimeWire is a file sharing application running on the Gnutella Network. It is open standard software running on an open protocol, free for the public to use. LimeWire allows you to share any file such as.mp3s, .avi's, jpg's, tiffs, etc. Limewire is written in Java, and will run on Windows, Macintosh, Linux, Sun, and other computing platforms. Publish your original content to the world without setting up a website!


Why Should I Use LimeWire?

At LimeWire, we are working on developing the future of open peer networks and the digital commons. Our goal is to build users a tool that allows them to easily publish content to the world. LimeWire's elegant user interface is like no other Gnutella application available. LimeWire is capable of multiple searches, available in several different languages, and is most famous for its ease-of-use and cross platform compatibility. LimeWire offers two versions of the software: LimeWire Basic which is ad-supported and is free of charge; the other is LimeWire PRO which is $9.50 and contains no ads or flashing banners, includes 6 months of free updates, and customer support via email.



I hope this helps you. You should also take a look at the User Guide.