Hi, I found these on-line:
http://archive.org/details/IbmPcjrTechnicalReference
http://ibm-pc.org/manuals/ibm/5150/Pcsim1-9.pdf
Paul
ibm pcjr technical reference manual
Re: ibm pcjr technical reference manual
Yup, I used to use those PDFs all the time. I found it to still be well worth buying a paper copy, though. 