A few off the top of my head:
http://www.jensense.com
great resouce on pay per click programs
http://adwords.blogspot.com
the official adwords blog
http://adsense.blogspot.com
the official adsense blog
http://www.sewatch.com
the daddy of SEO sites
http://www.seoresearchlabs.com
good free SEO download
more to come.
post yours