dpreview is in general a fab site, and my first stop for almost any information photographic.
Anyway, they’ve posted an item about a new design of sensor for digicams that genuinely records RGB in a single chip:
www.dpreview.com/news/0708/07080901nikonimagesensor.asp
They’ve got a link to the US Patent Office with the full details, and this includes a short explanation of why a single sensor doing true RGB is a good thing!