I'm new and I am trying to get started with OS-X

I bought my first Mac a year ago December, and I love it. I have been interested in trying to write my own programs and don't even know where to start. I have never written any software before and was wondering if anyone could give me some recommendations on any books or other good websites that can help me in my quest. I want to start small with maybe making my own widget or something, but eventually I would like to expand into writing an autoshop POS system similar to RO Writer. I love OS-X and will never go back to using Vista ever again, and I would love to learn more about my beloved Mac. Thanks!!

Most OS-X apps that have the "desired" OS-X look and feel are developed in Cocoa.
The tools used there are Objective-C and Xcode.

I would start by getting your feet wet with something useful but not as in-depth as Cocoa.

Dave Taylor 'Learning UNIX for OS-X Mac' - this one is for Tiger. There are others for later releases of OS-X. This introduces you to console and bash programming

Thank you so much for your help...I really appreciate it!