Fractal Forge is an application written in Delphi that lets you easily explore the branches of the Mandelbrot set. It has received several very positive reviews.
This is a fantastic program! Easy to use, plenty of options to tinker with, and fantastic results. It even runs well on Linux with Wine (I'm using a Lenovo U260 with an Intel i5 processor and Linux Mint 11 to make that assessment). There is only one bug that I can find--the multiprocessor algorithm stops all sectors when one of the processors finishes its task, leaving the image with one computed sector and ($number_of_processors - 1) incomplete sectors. The single-processor algorithms, however, are quite satisfactory.