The site you want to go to is Search Engine Watch (dot) Com
Anything anyone tells you is correct, for the moment, then it changes.
When you deal with companies and SEO the hardest thing to get through to them is this fact.
One of the hardest things for companies to get through their heads is the low click through rates and even lower converstion rates. For instance, Amazon and eBay have the highest click through rates of any Internet sites. Amazon is in the high 20 percent and eBay in the low 20 percent. That means when you see ads or even come to Amazon through a search engine, less than 30% of all visitors will click.
The conversion factor (meaning an actual sale from that click) is even much lower.
A sucsessful Internet campagin is measured in tenths of one percent. But sales people are used to MUCH higher numbers.
Most web desginers are artists and woefully lacking in SEO. SEO depends on words and meanings of such.
The other key thing to understand before you dive in is page rank. It’s really not all it’s cracked up to be. I know from small sights I run, it isn’t always what you think it is. Google definately has gotten away from it.
Furthermore you have to understand EACH PAGE on your site has a rank as well as the overall site. And the two ranks are independent of each other.
Also page rank doesn’t count proportionally as you go up. And no one but Google (or whatever search engine) knows for sure.
For instance, if you have a page rank of 5 let’s say. That may be worth 100 points (I’m making this up for an example to show you)
A page rank of 4 may be worth 500 points, but a page rank of 3 may be worth 50,000 points and a page rank of 2 may be worth 325,000 points and a page rank of 1 may be worth 1.2 million points.
Now again, I made those numbers up to show you how you can be fooled by page rank. Since no one really knows it leads to what many call an undemocratic process.
Let me give you an example. Your keyword is Markxxx. Because I’m so famous everyone searches for me 
Let’s say the Straight Dope has a page rank of 2. So a link to my site FROM the Straight Dope would be worth 325,000 points. But let’s say the New York Times also puts a link to my site. And the NY Times is a page rank of 1. This would be worth 1.2 million points.
So you could have three greats sites linking to me. If each of those sites had a page rank of 2, I would only have 975,000 points. Whereas a single link from the NY Times would give me 1.2 million.
This is why Google is often called “undemocratic,” because an established link from a page rank 1 site can be worth more than three others combined.
Finally remember page rank is based on keyword or key phrase and changes. My above example is for the keyword Markxxx. But the NY Times could have a page rank of 1 for the keyword Markxxx and a page rank of six for “light bulbs”
So start at Search Engine Watch and read through the forums. Remember Google and Yahoo and others don’t want you to know what they are doing, so SEO is going to be a constant thing. You change the site as Google (and others) change their methods