For the most part, in consumer electronics the P and C labels are interchangable, since they are often used incorrectly.

The official technical difference is that Y/Cb/Cr is for digital video and Y/Pb/Pr is for analog - however nothing uses digital video over component (yes, 480p, 720p and 1080i over component are all analog - for digital video you need to use DVI or HDMI). So I guess you'll have to go by the manual as for which does what. :-)

Thanks for the comments!