Getting Started with AppleScript—the Tools You Need
The AppleScript language enables you to execute commands. To do this, scripts can be as short as one line of code or extremely complex. Here is an example of a simple script:
display dialog "Introduction to AppleScript"
When executed, this script will launch a popup box with the words "Introduction to AppleScript" in it.
The tool you use to write and compile your scripts is the AppleScript Script Editor. You can find the editor located in the folder /Applications/ AppleScript.
With the Script Editor, you have access to all you need to help write your scripts and compile them. The compilation of AppleScripts is especially important because this is how you can package and distribute your new solution. The Script Editor allows you to compile your scripts as compiled scripts, applications, bundled applications, or plain text. The plain text solution is good to have if you want to email your code to another developer.
You will find that over time, Script Editor is good for simple AppleScript solutions that you will build. However, debugging and other tighter integration with the OS are rudimentary. If you're going to become a power programmer then you'll be looking to use other third-party products.
Additional products are available to help you with your scripting needs. One of the most powerful is AppleScript Studio, which gives a complete development environment that is tightly connected to the OS. If you're a power AppleScript developer, you'll want to check out AppleScript Studio.
There are other solutions on the market (such as Smile and others).