Python [http://www.python.org] is a popular ScriptingLanguage in the UNIX community and beyond. Python is object-oriented [“multi-paradigm” is the preferred classification] and easy to extend with libraries written in C, which makes it possible to write really fast programs, really fast.
Other commonly cited strengths are:
The current version of Python is 2.5; OS X 10.4 ships with Python 2.4.
You can use Python + PyObjC to create Cocoa applications! It’s not perfect and YMMV but you can find the bridge here: [http://pyobjc.sourceforge.net/]
py2app [http://undefined.org/python/#py2app] converts Python scripts into Mac OS X applications.
There’s a very good introductory tutorial by Jonathan Rentzsch on Apple’s developer site: [http://developer.apple.com/cocoa/pyobjc.html]
appscript [http://appscript.sourceforge.net] allows Python to control scriptable applications in place of AppleScript.