Reichart,
There are several programs which do EXACTLY what you describe. They sit in the system tray and when you visit a page that matches enough words in the commerce catcher, it offers to fill in all the credit card, billing, etc. fields with any of the credit cards your PC is aware of.
The one that seems the most common is
http://qwallet.com/
Or you can use MS's sell-your-info-to-anyone "Microsoft Wallet".