If I recall correctly (it's been a while), the normal Mandelbrot works by treating each pixel as a complex number and seeing if it escapes to infinity or not when iterated through some formula... the Buddhabrot however plots which values are landed on as numbers are iterated...

An interesting alternative I tried some years ago is to draw lines for each iteration instead, between where it started and where it ends, leading to the following result:

http://img40.imageshack.us/img40/583/pathsoftravel5.png

(I have some C code lying around if anyone's interested.)