Ask HN: Where can I learn to make websites for cell phone browsers?

I live in Japan and do web development on the side occasionally; one of the things I'd really like to be able to do is make websites suited for cell phones here -- not for large touch-screen phones, which can usually use a normal site, but the standard Japanese phone that uses a mobile browser (for example, mine [Sharp SH003] uses Myriad).

I've noticed that some standard HTML tags don't work and that there are other, undocumented ones that allow you to do things like dial a phone number.

I've had a very hard time searching for this kind of information in the past, so if there are any keywords that stand out for this type of web programming, please let me know!