Yeah PHP/mysql will do the trick for what you've described. MySQL is a decent database for even some large-scale apps. PHP is a decent scripting language for webapps that doesn't have too steep of a learning curve. I wouldn't make anything too big in it, i'd probably go java/c# for that, but you're probably fine with it for a small/medium app. AFAIK, vBulletin is written with PHP/MySQL behind the HTML and it's served up some very busy forums if you have any performance concerns.

I learned both from W3Schools Online Web Tutorials many moons ago. That should get you started far enough that you can just use google as a reference for more specific things you'll need to know.