There are lots of zigbee modules are avaliable in market which supports serial communication. which module you are using ? and which communication protocol it supports
Since you say you will be using a PIC32MX795, I'd like to suggest the MRF24J40MA module. You should be able to use the SPI interface. The MRF24J40MA datasheet even explicitly states it is compatible with the PIC32. I recently bought a few of these very same modules at Mouser...