Acrobat Reader is available from Adobe
for the pocket pc. It should be possible to copy some or all of the pdf files from the NEC CD-Rom to your pocket pc using your pc. I'm not sure of the exact steps for the HP. I'm also not sure how much of the NEC will fit into a pocket pc, but if you limit it to the parts you are interested in, you should be able to load a useful amount into your pocket pc.
If you want to fit more of the NEC into your pocket pc, you could try something like pdftohtml
to convert the NEC to html and load it into your pocket pc. However, I would expect to loose important formatting information if you do so and possibly even change the meaning of some sections.
You can also extract just the text from the pdf with something like pstotext
, but I would expect the results to have lost all formatting and only be useful as a reference to someone with a lot of experience.