Found this while lurking DFO-Source/SSA
ASPS: Dungeon Fighter Online Skill Simulator
Missing Priest, but very useful tool because levels and SP Book quests can be adjusted. Also features "Max-out" that keeps your skills updated as you click level up, which is awesome for determining what to spend your SP on in the near future.
Also requesting this be put up on first post.
AradSociety
Everyone should be familiar with this already. Very simple and easy to use, but lacks a few things and gets buggy randomly.