Be careful when downloading KaZza... or any other service like that. Unless you read the pages and pages of fine print before clicking "I agree" you'll never know that they are installing other things on your computer.
When I downloaded kazza I thought it was going to be cool, but the next day my computer started acting like it had to much going on at one time to handle itself... and it would just dissconect. In fact it wouldn't stay connected for more then a minute or two. So I started getting pissed and desperately tried to find out the reason why this was happening. So I clicked Ctrl,Alt,Delete to bring up the program box. I noticed that there was something running there that I never seen before. (The name is ezula) Anyway I was going to delete it, but I didn't want to screw anything up. I mean I really didn't know what the program was and I thought maybe I just never noticed it before. So I just searched the name of it on yahoo. There I found a ton of pages about it and what a pain in the ass it is. It seems that these companies like KaZza take money from other major companies (i.e. BMG) and in return KaZza installs this other crap on your computer that actually monitors your search habits and changes link desinations. So say that you always look up a certain type of music or movies. Well, this thing figures that out and eventually starts changing shit around. Let's say that you are looking at a page with a bunch of links to different "Horror Movie" sites. Well what this thing does is change a few of the links, so that they no longer go to where said link was originally supposed to go (i.e. some guy selling old films out of his house) and takes one of their customers pages and links it up. So now you go to their clients page instead. Sometimes they even go as far as to highlight the link so it stands out more.
Not only are you have your search information force fed to you now, its actually sitting in your computer where it can cause problems like it did me. Also, guess what? Its completely legal. Know why? because you clicked "I agree" upon downloading.
If you are affraid that you might have this go to:
http://www.whirlywiryweb.com/q/ezula.asp There you will find that the site will actually check and tell you if ezula has infected your computer