I have written a fractal explorer called Fractoid. It is available on the market for phones running Android 2.0.1 or higher.
I've released the source code under the GPLv3 license, and its available on GitHub:
dbyrne's Fractoid at master - GitHub
If you want to see some fractals I generated with my droid, check out my picasa album:
Picasa Web Albums - David - Fractoid
Fractoid features: pinch to zoom UI, 10 different equations, Escape-time and various orbit trap coloring algorithms, Mandelbrot and Julia type fractals
Let me know what you think! I'd love to get some feedback on what should be added, changed, or removed. This project is still under very active development, so developers or fractal mathematicians who want to contribute are more than welcome.