Approach to switch from http to HTTPS

Hi,

We have a web enterprise application based on ASP.NET (3.5), IIS 6 that uses HTTP protocol in production for some time. The security department has asked us to switch as soon as possible to HTTPS. I would to know the best approach in order to implement to be sure to not forget some points.

For me all URLs have to be checked and http replaced with https, certificates have to be deployed in IIS web server

Is there a setting in web.config to force all data exchangebetween client browser and web server with HTTPS ? 

Thanks a lot

Regards