I think what that means is you can program one of those Parallel pin and use it your clock source. I guess there is one clkout pin out of MPC8260. To be sure, go to www.mot.com and search for the AppNote on that subject.
The 8260 is a sophisticated piece of silicon, beside the core based on the 603 there is a separate core called CPM. I recommend you to read the data sheet. The 8260 is designed for multi channel high speed communication applications, typical telecom.