Link :

XaoS is a real-time interactive fractal zoomer. It can display the fractals in X, svgalib, and even plain text mode.

It displays the Mandelbrot set or one of 8 other fractals and allows you to zoom smoothly into the fractal. Various coloring modes are provided for both the points inside and outside the selected set. In addition, switching between Mandelbrot and Julia fractal types is provided.

Other features include autopilot mode, palette changing, image saving, fractal inversion, and a built in fractal tutorial.

Already packaged in the main Debian archive by Manu Chao