You can use the
Student Edition C18 compiler from Microchip which is free. The only difference is that the Extended Instuction set optimizations are disabled after 60 days, but the compiler is still completely functional with the standard PIC18 instruction set beyond the 60 day mark.
The download link to the Vex default code should be on vexlabs.com when it is released, or you can email
info@innovationfirst.com to get it now if you really want it.