Where you buy the domain does not matter. It is where you do the hosting that determines what languages you can do. ... Most places offer html, css, and javascript. The small hosting company I run also does PHP and MySQL
I hate to talk bad about Yahoo, but I will never recommend anyone to their hosting again. They have raised their renewal price from about $9 per year to about $35 per year. I have over 20 domains and all of them are being moved to GoDaddy as their time for renewal comes up. I would recommend that you go with GoDaddy too.
If you know anything about PHP, search for a linux host. If you know ASP, search for a windows host. Once you pick a host, you will have to point your domain to it. (fairly easy if you have someone explain it) Which ever you choose, you will be fine using HTML, CSS, and Javascript.
