DNS-BH – Malware Domain Blocklist
"The DNS-BH project creates and maintains a listing of domains that are known to be used to propagate malware and spyware. This project creates the Bind and Windows zone files required to serve fake replies to localhost for any requests to these, thus preventing many spyware installs and reporting.
This list is also available in AdBlock and ISA Format..."
To install the AdblockPlus extension in Firefox, click here:
Blocking malicious sites with Adblock Plus
"... another layer of protection..."
Scroll down to: "... click here to subscribe to the list in Adblock Plus..." and click on the link - click OK to the popup for "Add subscription" - done.