Free Technology for Teachers posted a great link to PaperRater a free service designed to help high school and college students improve their writing. It checks your spelling and grammar but also checks for plagiarism – almost like TurnItIn that most South African universities use.

Paper Rater scans students’ papers then gives students an estimate of the likelihood that someone might think that their papers were plagiarized. Some of the other useful features of Paper Rater are style indicators, word choice evaluators, and a vocabulary sophistication indicator

Applications for Education
Paper Rater could be a valuable tool for high school students to run their papers through before turning them in for a grade. Paper Rater can make students aware of potential acts of plagiarism. Paper Rater can also make students aware of changes in vocabulary that they may want to make before submitting their final papers.

To use the service you have to register, but it’s free and an easy process. It took seconds for me to upload a document and see Paper Rater‘s comments: