How can i backup my itunes

Great feature that I just started using is Time Machine. All you need to do is set it up and it will do the rest for ya. Lloyd

 

I second Lloyd on that. Go to System Preferences > Time Machine, choose the Disk you want the backup to be on, and you're and press ON.

 

Cloud solution perhaps?

First of all, I'd like to say well done for thinking about doing this before anything bad happens

Time Machine is a good idea (you'll need an external drive for that, unless you want to use your internal drive, but using an external drive is easier), but I think a 'cloud' solution is good as well (A 'cloud' solution is basically where your files are backed up to a secure location via the Internet). Carbonite is one such service. Be aware that you have to pay for this though

If you don't want to do that, though, iLounge has a very comprehensive guide to backing up your library of content.