The below takes you ssl.com aritcle on web page secure. This brilliantly written article answers almost everything you need to know bout how to tell if a website is secure.
http://info.ssl.com/Article.aspx?id=10068
Also read the below releated articles on subject:
http://www.iisfaq.com/default.aspx?View=P20&P=145
http://www.lloydstsb.com/security/web_page_security.asp [click 'check a site certificate' link at the end of description]
Below article explains the process of procuring and installing a SSL server certificate [article focus on SSL.com products, but worth to read as the process should be common to all vendors]
http://info.ssl.com/article.aspx?id=10694
Cheers