1. Go to http://domains.lycos.com and login with your username and password - there is a link in the upper right hand corner.  If you have forgotten your password, there is a link for that as well
  2. Select "my domains"
  3. On this page you will see a list of your domains (if you have more than one - click that domain name to select.  If you have only one domain, skip to step 4.
  4.  Now click the "general" tab.
  5. Next, click the "credit card" link.
  6. If you have changed credit cards, or the information has changed, click "create credit card" then fill in the information.

It's that simple!