Obtaining an SSL certificate for your website is a task that every IIS administrator will have to perform at some point in time. This can be a confusing process the first time you have to do this. IIS7 has changed the way that certificates are requested. In the IIS6 days, you requested a certificate from within the specific website properties. In IIS7, there is a configuration section labeled Server Certificates where all requests for SSL certificates originate.
The initial request and completion of the request is done via this interface. Click here for a guided walk-through of this process.