Chris Adams has started a series of posts about SSL and how it is implemented in IIS. In his first post he focus on IIS 4, 5 and 5.1 and how they differ from IIS 6.0.

Read Part I of his SSL series at source: SSL Part I.

He has done several other articles about SSL:
Dealing with Secure Socket Layers (SSL) issues & IIS.
Windows Server 2003 Service Pack 1 AND IIS 6.0: Host Headers & SSL.