The best way to learn how to code vBulletin templates is to work with the default set, once you begin to make changes to the templates you will start to understand where thing are and how stuff works.
If you would like to request custom work you can do so in the service requests forum on this site, there are also many sites around the net that do custom work and have galleries of their work on their site. Personaly I recomend finding a good skin site and doing research about them on 3rd party sites.
I would give you more info on coding vBulletin templates but I have to be at work in 30 minutes or so and hav'nt even ate or gotton a shower yet

, when I return ill make sure to reply to this with more info.