Kerry on "Cannot login to Wordpress suddenly"

I should have said, I've cleared my cache and deleted cookies, of course.

I clicked on a specific post from my Google Reader feed to try to get in from there, but I receive a 'too many redirects' error.

I looked here:

http://codex.wordpress.org/Login_Trouble#Site_URL_Redirecting

Where it says: "Check the siteurl value in the wp-options table of your WordPress database. A guide to doing this is available here."

"Here" links to http://www.tamba2.org.uk/wordpress/site-url/, which is an empty page, at least to me. I'm not sure how to do this.