Owater,
A small question with many many answers... If I read you correctly you have no experience with programming languages. Now that implies you first need to learn at least one. When you start learning a programming language you will also need to learn ProjectBuilder, the I(ntegrated) D(evelopment) E(nvironment) that comes free (downloadable) with OS X. Once you get yourself going with one language you will be able to take up other stuff as Interface Builder and extend your applcation with stuff as AppleScript.
As a nice start to any pgm language you might take C (pls. see the other discussions on "which" language).
When you start with C you can start from the very scratch. Most books on C take in account the Unix platform but do not treat the OS X PB IDE.
So let me help out here. Get yourself a book on C programming with rave reviews on amazon.com (you don't have to buy it there
.
Start ProjectBuilder (you'll have to OK some defaults initially) and choose:
1) ProjectBuilder>File>New File.
2) Choose Carbon>C file.
3) Type a file name fi 'test01.c' and
4) Deselect "also create" 'test01.h'.
5) Set Location: ~/
6) Add to Project: none
7) Click "Finish" or <Enter>
Now PB's editor starts up.
8) Remove the #include carbon statement.
9) Now start typing your first book lesson, probably something like:
int main() {
printf("Hello World\n");
}
and !Save the file.
10) Open Terminal (it's in Utilities)
11) Type: cc test01.c <Enter>
cc invokes the compiler, test01.c should be the name of your abive saved file.
12) Now type: ~/a.out <Enter>
You will see the 'Hello World' text being printed on the terminal.
This way at least you can start learning to program from the book. You will learn PB along the way later as it is a very very nice tool but it reacts 'strange' to these simple programs from the books with scanf and printf statements. For simple C programming choose 'C tool' when you open a project in PB later.
Notice your file and a.out in your home directory.
Good luck whichever way you choose to go! Small tip, finish the book(s) completely (as most people stop half way) as that will make you a good programmer.
Hope this helps