Tips needed from Progamming GURUS :P

Hello everyone, Actually i am a designer. But i was thinking of further carrying out some studies and get into web development also. As my clients always ask me to code the wordpress sites or template sites. Now my question to the gurus is that please guide me abit. I mean where should i start and end. FOr example i am noob at programming but i do know programming language C , which i think is kind of useless of site development. Maybe i should start with html and where should i end then. Just i abit confused.

Try this one http://rockablepress.com/launch/building-wordpress-themes-from-scratch/