Yes.

Start pdebug on your target like this:

pdebug /dev/ser1[,baudrate]

(assuming your serial is at /dev/ser1)


then, from your host connect using

(gdb) target qnx /dev/...

where "/dev/..." is your serial port on the host side.


You can see more in our online documentation: 
http://www.qnx.com/developers/docs/660/index.jsp

search 'pdebug'.


HTH,

Aleksandar