How can I make a gradient like this? (Edge between colors is hard, and bends)

I'm using Illustrator CS5

Looking to make a gradient similar to the one in the "BubbleBoddy" font here -

What's the smartest way to go about doing this? I have a basic understanding of gradients, but I have no idea how to get the gradient line to bend like that, or how to get such a "hard edge" between the light and dark pink.

Any help is greatly appreciated! Thank you!