WordPress 1.3 will enable you to use Themes to design and style your weblog. Work on this feature has been in progress for quite some time now. Work started back in September. Now the shape of things to come seems clear.
The next version of WordPress will have support for user-defined themes built in. Until now, WordPress used index.php and the comments-files in conjunction with a CSS stylesheet, to control the way it presented the content when published. All other pages, including the category and archive pages were actually generated by passing parameters to the index.php page. The introduction of the theme system does not mean that the old method of styling papges will not work. If you are upgrading from v1.2 or v1.2.1, users have the liberty to continue using their existing design, without switching to the new system. The new Theme system will provide a method for you to define different physical (.php) files for the different components of your weblog. Let us call each of the different physical *.php files a template. So, with the new theme system, you can define different templates for the category archives, the monthly archives, the individual-entry pages etc.
If, as a designer, WordPress user, or developer, you want to get a head start in creating themes, please visit the Theme Development page at the wiki. Now would be a good time to bring any concerns or suggestions you may have regarding the Theme System. You can leave comments at the Theme Development Discussion Page, or discuss it in the hackers mailing list or the beta discussion forum.
Please feel free to improve the pages at the wiki, they are all yours!