According to Ars Technica the next version of Mac OS X, version 10.6 code named Snow Leopard, will not only be Intel Processor only, it may be Cocoa only! Cocoa is Apple Inc.'s native object-oriented application program environment for the Mac OS X operating system. Cocoa is derived from programming environments developed by NeXT in the late 1980s. When Apple bought NeXT, and brought in Steve Jobs, the former NeXT operating system became the basis of Mac OS X and was based on Cocoa.
Carbon is Apple's Application Programming Interface (API) for the Macintosh operating system, which permits a good degree of forward and backward compatibility between source code written to run on the older and now dated "Classic" Mac OS (Version 8.1 and later), and the newer Mac OS X. A lot of older, pre-Mac OS X, applications became Mac OS X compatible by using Carbon APIs.
What does this mean? It means that after Snow Leopard is released, and new "must have" applications are released that require Snow Leopard, compatibility with older applications that are Carbon based (and won't run on Snow Leopard) may be broken, forcing them to be upgraded (or replaced) as well. This could have significant impacts on our university computer labs.