Hoss is right, the program does what it says and does it very well. However, if you by chance happen to be using Firefox, check out the "AdBlock Plus" extension. It's completely free and updated frequently.
If you really wanted to get down to business ad-killing and wouldn't mind keeping it updated, a Host file REALLY destroys them. For that, I think MVPs Host File is one of the best. Before you do that though, check out these two places: http://www.mvps.org/winhelp2002/hos... and http://www.accs-net.com/hosts/eDext...
The reason EDexter is brought up is because some of these ad-servers are used by legitimate services, Akamai being a prime example. It's an ad-server that is blocked by the Host file, but the problem is, Microsoft uses that server to do Windows Updates.
Basically what EDexter does is instead of completely blocking access, it tells the server you are there but "filters" what that server sends back. So Windows Updates get through, but ad-servers who just send ads, when they try to send it back to you, EDexter puts up a small image (usually a colored tiny line by default" in place of the ad.
It's hard for me to explain, but be assured it works. Now with a Host file and AdBlock Plus both, lol, you get to a point where you forget what an ad is :-) But if you don't want to go through all that (not that it's complicated btw) and don't mind paying for AdMuncher, AdMuncher is great.