It sees more and more webmasters are using CSS for the design and layout of their sites rather than depending on tables and HTML mark up. As well as being more efficient in terms of page size and reusing CSS templates many webmasters believe that it also contributions towards search engine friendliness.
Jacob over at Blogging Pro has written an article based on his personal experiences and points out what he believes to make a better more search engine friendly site.
For a long time I have always loved using tables for site layout, but the general consensus is now that tables are bad for layout. I agree once you start nesting tables things start to get complicated and messy. All of this extra HTML in your page gets in the way of the real content that the search engines are after. If you separate design from content the search engines can just crawl the content and ignore the design.
Separating content from design also means that pages are much easier to update, rather than having to rewrite every page all you need do is alter the stylesheet. This saves you no end of time and saves you no end of bandwidth, the browser only has to pull down the stylesheet once if you use it for all of your pages. Not only have you saved on bandwidth costs but you have speeded up page loading, this is good for both your visitors and the many bots that crawl your site.
I have started to use CSS in more of my sites and I am going to use CSS solely on my next site which means learning about how CSS is used for layout. One of the sites that I have found useful is the Web Design Group where they have a guide to cascading style sheets. The site also includes lots of links to other CSS resources.
If you are not using CSS it would be well worth your time learning the CSS tags and their properties. Think of it as a future investment, the time you spend now will pay for itself in better search engine ranking, saved bandwidth and you will cut down on your maintenance and development time for your new sites.