This Application converts movies (like avi, mpeg, mov, most that quicktime plays) to gif format. You can choose output number of colors, size, frames to skip and section of movie to convert. The convertion is done via a multithreaded queue system which performs well on a dual core computer, and ok on a standard.

I use libgd for this app which works well except for I havent found a way to create a global pallete given the set of frames (so the convertion is always done in a single pass).