Here are a few quick links:

SEOmoz.org

A good article about one aspect of a good SEO strategy — conversion.

SEO Chat

Wikipedia actually has a great article on Search Engine Optimization at the time of this writing.

The 5 Don’ts of SEO — A Quick Guide On a related note the SEO.com Blog is awesome.

My pal Hristo Hristov, the author of SEO Board, has a FANTASTIC site about SEO and you should definitely check it and his forum software out.  (And I say pal although I haven’t talked to him in a couple years now I think.)

This one (http://www.seoadministrator.com/) is a particularly sneaky trick I’ve employed for years.  Check out the long listing of all the available features and then research them on your own!

I do this with college course listings, program offerings, et cetera.

SEO Book has a tools section that is fairly stellar.