Controlling iTunes Library from External Hard Drive?

You can either put everything you don't use in your CPU on your WD Book and have more space in you CPU for more music or just move all of your music to your Book and direct your iTunes library to it's new location....either way have fun, I have a WD Book and moved all of my music to it but didn't like the slight pause (and I mean slight) to get my music playing so I put everything I didn't need or use from my CPU into my Book and used the extra space on my CPU for my music..