I just try to wear clothes that hide the jiggle and use it to encourage me to run, because some day, I will be able to run without anything flopping around. Until then, tight sports bra, supportive undergarments and long t-shirts.
High-waisted compression shorts/capris/pants! I like them to be nice and tight on my stomach so that everything stays in place and I don't have to even think about my tummy moving around during a run.
I wear compression clothes too. They are more flattering. They don't rub or ride up and they breathe, so you don't get hot. And I guess, they prevent the jiggle which wasn't what I was worried about, but it's a nice side benefit.