In order to set IIS 6 to respond HTTPS requests the server must be configured with Certificate.
The certificate can be requested from Certificate Authorities, or you can simply self certificate the server.
For the second option you need to follow these simple steps:
1) Download and Install IIS 6.0 Resource Kit Tools from:
http://www.microsoft.com/downloads/details.aspx?FamilyID=56fc92ee-a71a-4c73-b628-ade629c89499&displaylang=en
2) Once IIS Resource Kit installed, open IIS Metabase Explorer (Start menu->Programs->IIS Resources->Metabase Explorer). Go to LM->W3SVC and select the items on the left to see on the right a description of them and find your virtual site (the default Web Site usually has ID 1). At this point, suppose the site has ID=123 you have to issue run from command prompt (you might need to change current directory to ‘Program FilesIIS ResourcesSelfSSL’):
SelfSSL /N:CN=yoursite.yourdomain.com /V:365 /S:123
where:
/N:CN is the name of your site on the internet (or LAN)
/V: sets the number of days before the new certify expires
/S: is the ID we found
After this command line is completed, the site is ready to go.