Creating Applications For Mac

As of late, I've really become interested in designing and coding applications for Mac. I have an idea of where to start, but I need some help.

I'm a high school student, so money isn't exactly something that runs in abundance. I run 10.4.11 on a somewhat old eMac. It's a 1 GHz PPC G4 with 640 MB of RAM. Definitely not exactly "top-of-the-line" equipment.

Unfortunately, Apple's XCode 3 can't run on my system, and I haven't found an XCode 2 download anywhere. I bought my computer used and it didn't come with any install disks. I feel as if I've hit a brick wall.

Is there any alternative to XCode? Or is there anywhere where I can download XCode 2? Any help would be much appreciated.

Thanks!

-Nathan