Via Gary Matt Cutts recently wrote a brief article about how Google works. It does not go through all the advanced spam filters layered over the top, but is a good beginners guide to how search engines work.

Matt Cutts also did an audio interview on WebmasterRadio, talking about many webmaster related issues. A few things Matt notes:

• Some people waste too much effort going after a trophy phrase instead of going after a broad array of easier phrases.

• Goes over some duplicate content issues at a low level.
• Start out with a niche and build out.
• It takes time to develop...don't expect a 4 day old site to compete.
• hidden text penalties can take 30 days to 90 days to lift, longer for multiple instances

A while ago Jeff Dean did a behind the scenes look at Google video broadcast.