I am using SharePoint Server 2007 Enterprise with Windows Server 2008 Enterprise, and I am using publishing portal template. I am developing using VSTS 2008 + C# + .Net 3.5. 

I want to know, How to add a WebPart to all pages of a SharePoint Site? 

Any reference samples?

I want to use this WebPart to display some common information (but the information may change dynamically, and that's why I choose a WebPart) on all pages.