Rather than using your real credit card number to shop online, you can use a secure, free one-time use number instead. You will receive a unique number that is linked to your actual Card account each time you shop.
Ask your credit card issuer about “substitute” or “single-use” credit card numbers. This new technology allows you to use your credit card without putting your real account number online, protecting it from abuse by “hackers” or dishonest employees of the seller.
I use this one. It is fast & easy.
http://www.mbnashopsafe.com/
More info available here:
http://www.dealchecker.com/doc.cfm?OID=1091