I'm not too computer savvy, but I want to know if there is a way to transfer my mobile apps on iTunes to an external hard drive? I am trying to free up space on my PC's internal space. And if so, how do I go about doing so?
The best way would be to set your whole iTunes library to your external hard drive. To do this, go to:
edit > preferences > advanced
There chance the "iTunes Media Folder Location" to your external hard drive.
Note that this will copy all your iTunes Media (Apps, musics, series, movies, and so on) to the external disc. I don't think there's a way to set just the apps to the new iTunes Media folder (but someone correct me if I'm wrong).
Another way you could go around this is to simply cut and paste all the apps from your Applications folder in your current iTunes Media folder to your external hard drive, but this has some implications: Go to the Advanced preferences pane section again (instructions above) and untick the checkbox that says "copy files to iTunes to iTunes Media folder when adding to library". In this way you can keep everything anywhere, so you can keeps your apps in the external hard drive. But this imply that nothing you add to iTunes will be copied to the iTunes Media folder, so if you are a freak for having the iTunes Media folder organized (I am), then this is not the option for you. But if you don't mind, you could even have your songs in one hard drive, your apps in another, and link them to iTunes by unticking that checkbox.
Backing up your purchases is one approach. Since iTunes provides access to your prior purchases (as long as they have not been removed by Apple or the Developer), you can safely delete them from your computer. That won't be enough though. You'll need to tell iTunes not to automatically download them. Here are the steps you could take: