Ye' old general discussion board. Basically, for everything that isn't covered elsewhere. Come here to shoot the breeze, shoot your mouth off, or whatever suits your fancy. This forum is not for asking programming related questions.
php works pretty well with any of the database APIs it supports. The fact that php4 came with MySQL built-in, helped push MySQL into "default" usage, as people are often too lazy or scared to change things, when one is provided by default.