What's available is what people share ... it's not a server that people downld from. So without having a Gnutella program like LW, then you wouldn't be able to see.
I don't know what you mean by join. If you're refering to joining the share network community or joining an site that wants you to pay for LW. LW is free unless you get the pro version. Get it here: http://www.limewire.com/english/content/download.shtml