[X-Newbies] New external hard drive

[Robert Green]

I have two questions. First of all I am running 10.4.8 and have just  
installed a new western digital my book external hard drive. If I  
want to defragment the internal hard drive using idefrag how do I  
boot from the new drive so that I can defrag it. The second question  
is can I move the itunes library  to the new drive so that itunes  
recognizes where it is. The library is currently about 19 GB.