Google and Yahoo read tables just peachy. The problem with tables and SEO is generally with how we use tables for layout. Usually we have our menu bars coded in the first table... and that table can run several hundred lines before our content tables that contain our text, headers, etc.

Google weighs the first couple hundred lines of your HTML more heavily than what follows below. If ALL googlebot sees at the top of your site is your nav bar, or your table spacers.... with no text, no headers, etc.... The Bot will take note and move on.

However, if you arrange your tables cleverly, so that what googlebot see's first is your content and text, then your text is at the top of the pages and gets read and indexed properly.