Hi
I’m new to WordPress, and I don’t know what your background is, but if you are familiar with (X)HTML it might not be that difficult. I moved my blog from MovableType to WordPress a few days ago, and it only took a few hours to convert the MT theme to a WP one. I found these two resources really useful:
This tutorial series takes you through building a WordPress theme from scratch; it helps you understand how themes work:
http://www.wpdesigner.com/2007/02/19/so-you-want-to-create-wordpress-themes-huh/
If you are converting an existing static layout to WordPress, this might be a good place to start:
http://www.jestro.com/web-design/convert-xhtml-css-to-wordpress/
I knew practically nothing about WordPress before last week; my newly converted site is here:
http://www.larecettedujour.org/
The CSS still needs a bit of tidying up, but I think it’s not bad for a few hours’ work 🙂