The color space faq previously at this site has been superseded by the one at:
http://www.poynton.com/PDFs/coloureq.pdf
Richard Salamon, Adrian Ford, and Alan Roberts are to be commended for the great job they've done helping us all understand this important topic.
The RGB->YUV conversions are given in Chaper 10 of their document.
As always, thanks to Charles for hosting their document as well.
Rick Davis <rld@well.com>