The OnLine Grammar Checker assists writers of any language by providing multiple, real-world examples of how many times the phrase is used with one of two largest search engines - Google or Yahoo. It check how often a phrase or word is used and in what contexts.
Grammar Slammer 4.2
Easy grammar help + reference.
Grammar Fitness 4.0
Improve students' grammar skills
Easy English grammar + writing help
Grammar + spelling checker + reference.
Russian Grammatical Dictionary