LimeWire Pro is an updated version of LimeWire.
It offers "faster download speeds" and all the rest.
The only thing is that people (including the previous 2 posters) think you actually have to PAY for this which is false. All you are paying for on LimeWire Pro is the support service of which comes with it.
Take a look at this link :
http://digg.com/software/LimeWire_Pro,_for_fre e,_legally_
It offers links where you can download LimeWire Pro for free. And it's legal because some of the links are actually from the LimeWire website itself.