ObjectFarmSpell is a spell checker (based on ispell) that plugs into Mac OS X's spell checking architecture. For most Cocoa apps ObjectFarmSpell provides spell checking in German, Spanish, Italian and French. More languages will follow soon.
ObjectFarmSpell plugs into Cocoa's spell server architecture and makes spell checking for multiple languages available. To be honest ObjectFarmSpell does not implement a real spell checker by it self but rather uses ispell as its spell checking backend. It's simply a wrapper service for a pretty common unix tool.