An SSL (Secure Socket Layers) digital certificate is an electronic file that uniquely identifies individuals and servers. Digital certificates allow the client (Web browser) to authenticate the server prior to establishing an SSL session. Typically, digital certificates are signed by an independent and trusted third party to ensure their validity. The "signer" of a digital certificate is known as a Certification Authority (CA), such as VeriSign. You can go through any vendor for your SSL Certificate.
Conventionally, URLs that require an SSL connection start with https:// rather than http://.
Contact a qualified IIS professional. Configuring Secure Socket Layers (SSL) is beyond our scope of support.