Moving App Storage Location iPhone

I am using a PC. My music and videos are all on my portable external HD. My Apps are all on my internal C drive. I want them on my External. It is extremely time consuming to move them and then tell iTunes where each and every individual app is, especially when every time it updates the app or I get a new app it puts it back on the C drive.
Will someone please tell me I can have iTunes move, keep and manage it on the external? And then tell me how to do it. LOL
Cyber
G3 iMac 700 DV Special Edition Mac OS X (10.2.x) Also iPhone 3G 1 Vista 1 XP Desktop 1 G3 iMac & 1 G4 iMac