You’re thinking of Scripting Bridge, Leopard’s new ObjC-Apple event bridge, which can be accessed from Python and Ruby via PyObjC and RubyCocoa as well as natively from ObjC. If you want to read more about it there’s a brief introduction at:

http://www.apple.com/applescript/features/scriptingbridge.html

along with various bits of documentation at http://developer.apple.com (some of it is in the Leopard devcenter which you’ll need a free/paid ADC account to access).

There’s also several third-party bridges available which can be used on Panther/Tiger as well; e.g. see my sig. below.

HTH

has

http://appscript.sourceforge.net
http://rb-appscript.rubyforge.org