Or you could just download the student addition free. You have to register first, but its free, then you can download the student version which is basically just a demo. It works fully for 60 days, so that should get you through OCCRA, and even after that, the compiler still works.
c18
The links are at the bottom, the one that says no documents worked for me. Remember you will have to register free first
"Student Edition/Demo
The Student Edition is free! It has all the features of the full compiler and libraries. After 60 days, the optimizations related to procedural abstraction and to the extended instruction set of the newer PIC18XXXX devices will be disabled. Code compiled after the expiration date will function but may occupy more memory space." From Microchips site
Hope this is a little easier.