You'll have to program each PIC individually. Program one, disconnect it, the program the other. For a test bed, you could simply set one PIC up as a continuous sender, and the other as a continuous receiver. The first PIC would just have an infinite loop, and inside would be some code to write out a short test message, like "Hello, world!". Once that device is running, you would connect to the 2nd PIC, which would be the receiver. What ever it receives, you could have it write out to another communication port (perhaps an RS-232 port, so that it shows up on Hyperterminal on your PC, or display it to an attached LCD, etc). There are LOTS of options on how to accomplish this task.