DNSKong (for Windows)
http://en.wikipedia.org/wiki/DNSKong
DNSKong is a free and small in lenght (280 KB) personal caching, filtering and blocking psuedo-DNS server application for Microsoft Windows operating systems. It is quite similar to hosts-file blocking principle with few advantages. The main principle is pretty straightforward, there are two basic configuraton files named.txt and pass.txt. While the named.txt file contains all the host-names you don't want any contact with them, pass.txt contains those entries that would be otherwise blocked, but you exclude them from blocking with it. There are many pre-set filters available to download in a packed taygas.zip file, the link is on DNSKong's home-site. DNSKong also supports filtering by the string only (filtering by only part of full host-name), and futher, it supports also the so-called Proxy DNS feature, meaning that you can choose up to five preferred DNS servers (ISP's Name Server IPs), and DNSKong will send each proxied IP your domain requests and will use the first successful response.
Finally, there is also another file called presets.txt (a cache of IPs and host-names, similar to a common hosts file), which contains the resolved IPs for the respective host-names to fasten the performance. DNSKong uses an internal memory structure for the cache and filters (a list of domain names along with the IP), and the presets are also stored in the same list. The cache is cleared each time you stop and start DNSKong. Also ,there are two "modes" or "ways of usage" that are most commonly used. One mode is to block-all the DNS traffic (with adding .com, .net, .org etc. into the named.txt file), except for those few sites that you visit on day-to-day basis, and you've added them to the pass.txt file, while another mode is to pass-all, except for those malicious strings or full host-names that you've added to the named.txt file.
DNSKong runs on Windows 95, 98, ME, NT, 2000, and XP. It is available as a zip archive or an installer.
The most current version of DNSKong is 1.43, released January 2, 2005.