Cocoa – Which GUI element does iCal use for calendar view

I’m writing a simple iCal-like app in Cocoa that I’d like to resemble the main view of iCal.

Does anyone know which GUI element (i.e. NSWhatever) was used to create the Month-view (this thing: http://skitch.com/edwardog/b38ba/ical)?

Thanks!

PS – A hint at figuring this sort of thing out for myself would also be well appreciated; I’ve got a feeling that the answer lies somewhere in .nib, but after poking around I didn’t have much luck.