I'm beginning the process of learning the ins and outs of developing sites for mobile web browsers. Are there any good resources/communities online that discuss mobile specific site development issues?

My initial understanding is that to cover different phones you need to build one site that is enabled for browsers with the webkit engine (iphone, android, etc.) and another more basic site for other older browsers, is this assumption correct?

Also what does developing for webkit mean exactly? How is it different than just using javascript/css/html? Is it the same except that you limit yourself to webkit specific functions and css? I looked on the webkit site, but it didn't explain it in those terms.

Are there any other snafus I need to watch out for when developing for mobile browsers?