It seems like SBApplication should work, but I haven't used it before.
According to @cocoadevcentral:
SBApplication: use to make cross-application scripting calls with Objective-C instead of AppleScript. Ex: get current iTunes track.
Here is is the excerpt from the documentation:
The SBApplication class provides a mechanism enabling an Objective-C program to send Apple events to a scriptable application and receive Apple events in response. It thereby makes it possible for that program to control the application and exchange data with it. Scripting Bridge works by bridging data types between Apple event descriptors and Cocoa objects.
Although SBApplication includes methods that manually send and process Apple events, you should never have to call these methods directly. Instead, subclasses of SBApplication implement application-specific methods that handle the sending of Apple events automatically.
For example, if you wanted to get the current iTunes track, you can simply use the currentTrack method of the dynamically defined subclass for the iTunes application—which handles the details of sending the Apple event for you—rather than figuring out the more complicated, low-level alternative:
[iTunes propertyWithCode:'pTrk'];
If you do need to send Apple events manually, consider using the NSAppleEventDescriptor class.
Hope that helps!