How do I show a loading animation after registration onclick event

The Blog Templates plugin usually takes a little over a minute to complete a registration. It needs to immediately hide the form and display a "loading" animation after someone clicks the registration button, instead of just sitting on the form for that long. When the registration is complete, the "welcome aboard" screen needs to appear.

A google search returned several solutions. What is the best solution to achieve this? Ideally, I would like to display a sentence or two (extolling features and benefits) with the animation.