How to transfer IIS6 or greater web site to another server running IIS7 ?

The best method is using the Web deployement tool:

if source server is IIS6, install Web deploy v2.1 available here: http://technet.microsoft.com/fr-fr/library/dd569059(v=ws.10).aspx

if source server is IIS7, install Web deploy v3.x available here: http://www.iis.net/downloads/microsoft/web-deploy

install also the Web deployment tool on the target IIS server.

Now, come back to our example: how to export IIS6 source web server ? follow the core tasks: http://technet.microsoft.com/fr-fr/library/dd568996(v=ws.10).aspx