itunes program on external drive

Can someone tell me how to download iTunes to an external drive? I record all of my music in wav format for the sonics so I fill my MacBook Air, iPods & iPhone up quickly. Because of that, I move my music around to free up space. The problem is that it's not formatted in iTunes so when I move it over to my Passport For Mac is doesn't save the artist names, album titles or song sequences. I have to enter them every time I move music back onto my laptop or iPhone. It's time consuming & a pain.
So...I'd like to just copy my iTunes program & library to the Passport but the Mac will not allow me to do it.
Can anyone help?
THANK U!!

The iTunes PROGRAM should not be moved from the Application folder. The iTunes LIBRARY (where all the actual music and data you're talking about) can easily be moved to an external drive:

How to move an iTunes library to an external drive | How To - CNET

Thx, Chas. Is there a way to copy iTunes on the external drive w/o losing it on my MacBook Air? I've moved a ton of music & vid to the x-drive but since I don't have iTunes on that drive it doesn't save the music in the proper format. I have to search for each track that I knew was an a particular album then re-input the info.

Thx again. Lemme know if u have any suggestions.