You can get the source by following these simple steps:

[Make a new directory called 'limewire' and navigate to that directory.]
cvs -d :pserver:guest@cvs.limewire.org:/cvs login
[hit enter -- a blank password is expected]
cvs -d :pserver:guest@cvs.limewire.org:/cvs checkout core gui lib tests

You now have the source.

You can also view the source online, if you prefer, at limewire.org.