Can I forcibly change where iTunes keeps my mobile applications? For the past few days I've been trying to move my iTunes library to an external hard drive, so that when I get a new PC in the future (as I'm doing right now), it's not a nightmare to get everything onto the new machine.  This, of course, means that it's a nightmare to get it all onto the external drive.

I think I've gotten the music and track info all sorted out, but now for some reason, when I sync my device to my library, it's removing every single application from the device.  On closer inspection, my 'apps' folder in iTunes is completely blank.  I'd like to not have to re-download everything since I had close to 14Gb of apps.

It turns out I'd copied the 'mobile applications' directory from my PC iTunes folder to the new drive without leaving a copy of it behind.  When iTunes looks for the applications, it's still looking in the old location.

I think I can temporarily avoid the problem by copying the app files back to their original location, but I'm wondering if there's a way to manually re-target iTunes's apps folder to a specified location.



EDIT:  So I copied the app files back, and iTunes is still coming up blank when I try to see the apps in my library.  How do I figure out where iTunes is looking for apps?
You have to go into advanced preferences in iTunes and you should see a box displaying your current iTunes Media folder location, with a button prompting you to change it.

If you select your folder there it should work for you. 

EDIT: 
A better way to move your iTunes content, is to move your entire iTunes library (you ~/Music/iTunes folder) into a new location. Then close and reopen iTunes while holding the Option key, when prompted to choose an iTunes library select the new location and everything should be stored in that new iTunes library folder (you can actually name the folder whatever you would like).