kung baguhan lang ka sa web programming, PHP is the better tool to start learning the concepts. PHP will allow you to immediately get to the core of doing web apps and not overwhelm you with proprietary libraries, plugins and whatnot. just stay away from frameworks at first and you'll do fine.
now kung dati na ka nga web programmer just go learn both and put them in your toolbox.
and oh, re VB6 for the web (not that i condone hijacking of threads

), technically any language or framework that can stream to the command line can be used for http apps. so yes, VB6 qualifies. at least for a masochistic exercise of webapp development