Move applications to different drive?

I have an old Mac that I lovingly refer to as my FrankenMac. It started life as Beige Desktop 233 MHZ G3. It now is a 450 MHZ G4 with firewire, usb, max memory, and a new video card. I'm running 10.3.9 on it and it runs very well as a file server, internet surfing, and word processing machine. Here's the problem, I still have it's original 4 gig hard drive in it and I'm running out of room. There is an external 160GB LaCie drive that has lots of room on it. Here's what I was wondering... Since most of my files that are growing are my user account and my applications, I thought I'd move them over to my LaCie and just leave the system files on the internal drive. I've tried to move my user file over by using an article I found on the web. I didn't do so well, I tried to do what it said to do, but it just tried to copy itself onto the same drive. Maybe if I knew a bit more about command line stuff I could make it work, but no dice so far. Would moving my applications over to the other drive be any easier? How would I do it without breaking any sort of links? Any help or advice would be appreciated! Thanx!

Isaac