I like to send home a letter at the beginning of each school year to give parents highlights of what to expect in my classroom. I outline my behavior plan, grading/school work/class work, class rules, etc. This helps parents remember highlights from open house night. It's also helpful if the student will have more than one teacher (departmentalized elementary school, or middle/high school) or if the parents have more than one child attending the school--it's hard to remember which teacher does what!
The screen shots below show what information I included in my letter from a few years ago. As you can see, it was written for a sixth grade class. To make things easier for you, I included a link to my Google Docs version of this letter so you can download it and format it for your classroom.
Click here to access the Parent Letter file!
I think it's important to keep this letter short and to the point. This letter is a little less than two pages. I have done a longer one, but longer doesn't always equal better.