Creating a calendar on a website that is accessible from a client

Finally the solution was very easy. A friend told me just to take a look at the google-calendar and that was right. At first it has all the functions I needed and you can include it without any problems into your website, you just have to copy a code-snippet that is also given by google and put that where you want to have it in your website. The next good thing was that it can easily be edited by the calendarfunction of MS Outlook or Mozillas Sunbird. They both can getting connected with the google-calender so you can enter and change data in it via client.