iTeachOrganizer app for iPhone and iPad

Now you can build your weekly timetable and send group messages based on it, or individual messages ( email, sms) based on time.
Features:
Group messaging by day. (SMS, iMessage (if available))
Group emailing by day. (iTO puts recipients into BCC avoiding privacy issues in your group)
Email, send SMS, add notes to individual students on given appointment time.
Add new lessons by manually typing names, and contact data, or:
Add new students to your schedule directly from your Address Book.
You have someone in your schedule already on another day of the week ? Start typing their name, you can finish the entry by clicking on the right name from the dropdown.
Set your default lesson duration in Settings, and save time by only having to add the lessons start time.
Set weekends on or off in Settings according to your needs
Rotate device in landscape mode to see your weekly schedule

Note: your service provider may apply charges for the sms and email messages