How do you want to secure it? I presume you actually need to serve pages on port 80 if so the best bet is make sure it is fully patched and make sure you include patches for IIS and if you are using SQL for the backend of the website ensure that is patched as well. If you are hosting any applications on the website then use the free tools from Qualys to check your site out as well. http://www.qualys.com/
no connection just a happy user of their tools.