Have you checked out the new HTML5?
The good news is that the same ddt is backwards compatible. The same ddt will read your XHTML and HTML codes and allow most of it. This allows you to combine new parts of your page in HTML5 with old parts of the page that you might not have time to update. It also allows you a free pass if you mistakenly code in the older XHTML for a bit.
Another bit of good news is that the current versions of most browsers already read HTML5.
HTML5 is designed to make organizing pages a part of the code. This allows for pages to be automatically outlined, organized into academic paper sections, referenced and cited, and slipped into ebooks. It has tags with properties that will replace much of the often-used Java Scripts previously needed to view videos, make slide presentations, and work with special media readers. Building on the XHTML, it has added tags to increase the functionality of the coding process.
HTML5 works in concert with CSS3. It is also an XML language, so you can build modules of code that are compatible with ecalendars, ebooks, ecards, address books and more.
Learn more by visiting these sites:
http://www.sitepoint.com/category/html-css/html5-html-css/ (This page lists 10 useful articles on the new HTML5 and CSS3.)
http://i.techrepublic.com./blog/webmaster/html5-the-next-generation-of-web-design/484?tag=mantle_skin; landing (This site links to 4 articles on the topic that are all worth reading. All 5 were used as references to my comments.)
http://www.webstandards.org (Which refers you to a free book download.)
To see how the code is developed, explore the site that publishes the reports from the working committee: http://www.w3.org and explore the links on website development, HTML, and HTML5. Drill down through the different pages to get a feel for how the information is presented. Then explore the new HTML5 tags. It can get intimidating, so be sure to read the pages mentioned in the above links first!