Currently Being ModeratedJan 12, 2013 4:50 AM (in response to NoKa-bavaria)
You are going to find this difficult to achieve.
Firstly, only calendars listed under 'On My Mac' can be published: you can't do this with an iCloud calendar.
When you choose Publish you will be asked to input the server details. However an ordinary website server won't do - that produces a text file with the data in a messy format. They rather expect you to be running your own CalDAV server, which I imagine you don't wan't to get into. There appear to very few, if any, CalDAV servers available but finding one is your only option.
If you can manage that, you can call up the calendar in an iFrame in iWeb or as an external link.