The newest version is shown as 3.4.7 (it might even be 3.4.8). Lots of changes in the last month.

LW should try to connect to others automatically (You can watch connections attempted in the View Menu->Show/Hide->Connections

Your iBook has a built-in firewall which blocks many kinds of internet connections. click on Apple Menu->System Preferences->Sharing->Firewall->New->to get at the pop-up list and choose the one that says "Gnutella/Limewire (6346)"

If you have a new iBook, you should also run the System Preference "Software Update." As a new owner, you should still have access to the 60 day(?) free AppleCare toll-free support.

You can check which version of OSX you are using in the Apple Menu->About this Mac.

If you are out of free support with Apple and want to know more about making sure your system is running well, http://www.macattorney.com/tutorial.html is a pretty good reference.