Sometimes you need to install your wildcard SSL certificate on multiple servers, for example, you may have your web server on one machine and you email server on another machine
1. Open up IIS and go to server certificates
2. Select your certificate, right click and select 'Export'
3. Select a destination filename and location for your pfx file and create a password. You will need this password to install the certificate.
The file you have created can now be imported into IIS.