LearnBoost, is an online grade book and lesson planner that is available for free to educators. It has a grade book, lesson planner, attendance, reporting and calendar. It is easy to use, visually appealing, and you can share information with students and parents. The lesson planner is integrated with state standards and you integrate the whole system with Google Apps.
I reviewed it in August and it's a great resource for any educator. Today they just announced that they have added a great new feature - Lesson Plan Sharing. Now you can share your lesson plans with other teachers, administrators, students and anyone else you'd like to. All the lessons you create with LearnBoost are shareable through their partner services (Facebook, Twitter, WordPress and more). You can also embed your lesson plans in your own web site and each lesson plan gets it's own URL.
This makes a great product even better. Check it out.