Can I backup my Itunes library to a network hard drive?

Sure, why not?

Time Machine, or chronsync, or just plain manual drag n drop.

 

Yes. Mine's on a Lacie NAS.

If I remember correctly you drag the folder with all the music in it from the iTunes folder under your user name to the NAS drive. Leave all the other files where they are. Once it has all been copied across, launch iTunes and go to Preferences then Advanced and click 'Change' under the iTunes Media Location header. Navigate to the copied file on your NAS and select it. ITunes will then start updating itself. What it's doing is updating the paths to the songs. If you don't let it do this the paths to each song will still point back to your original iTunes library.

The reason you leave all the other files in place on your Mac is that they store the playlist info etc. Also by doing this, as you add songs to your iTunes library they will get sent across and stored on your NAS and not your original iTunes Music folder (provided you've remember to connect to your NAS each time you launch iTunes). Once it's all working, delete your original iTunes library.

 

Maybe something like Acronis (although there has to be a cheaper option when you just want to backup a single directory). The iTunes folder on a Windows machine will just be in "My Documents\My Music\iTunes".

 

Anything you can use to automatically back up anything on your PC should be able to do this. You are currently backing up your system, right?