Are there any applications on the Mac OS X platform that were designed for compiling family tree information?

If not, any apps already on the Mac platform that are helpful to build a family tree? I'm thinking OmniGraffle on that one if nothing else already exists for family tree building.

Does anyone have recommendations on compiling this information? Applications to help compile and build this information? Sites that I must check out for info?

Any general suggestions are appreciated on this project as well...

Thanks!