Why does my 1996 Chevy Astro van make a loud pop when I go around corners with speed? When I go slowly,it won't make a sound...it happens when I turn either direction and its coming from the front end

sounds like a wheel bearing

I read somewhere that Astro vans are notorious for sway bar cracks...would that cause any of these issues?

anything is certainly possible, without being there to drive it and hear it, the only thing i can say is have someone you trust who works on front ends look it over. all steering and suspension parts, tie rod ends etc.