It's supposedly free and looks kinda neat.
Head of the Class? Free curriculum!?
anyway ...for free, it certainly is a good find! if you don't like it, no big loss, ykwim? it sort of reminds me of another free curriculum site that was also fairly good & was discussed here about a year ago or so...i wish i could remember the name of it. if i think of it, i'll post back though. you may like that one as well.
ETA: found it! http://www.lessonpathways.com/
I love it. I found it fairly easy to navigate and well worth the effort. You can select "custom curriculum" and only had the lesson plans you like as well as outside assignments from other sites. You can assign assessments by grade level as often as you like and then print them out for your records. It will also keep track of all the online assignments and grades. There is loads of online work to assign as well as many printouts. For the printout worksheets you have the option of entering the grade into the computer and the site will calculate it in with the online work and give them a grade for each subject. I like Lesson Pathways as well but this is by far my favorite.