John Chaffee has been making calendar related apps for Apple hardware for a long time with is involvement with Now Up-To-Date several years ago and, more recently, BusyCal. So when John launches a new product, I'm always interested. His latest venture is WhenWorks, an availability based appointment-setting application.

With this iOS app, you can set your availability and meeting type which ultimately results in a web page you can send out to invitees where they can select an available time. That selection then updates back into your calendar. Basically, it gets you out of the usual multiple-email calendar event setting game. The service integrates with iCloud calendar, Office 365, Google Calendar, and Outlook.

If you're interested there is a 14 day free trial and, after that you can schedule up to 5 events per month for free and unlock unlimited events for $5/month.