Affiliate Network where a publisher select advertisers whom he/she would like to promote. CJ takes care of tracking and make sure (almost 100%) that the publisher gets paid. As a publisher, you do not need to run after advertisers every month to collect money. I like CJ.
Create a niche website say about ringtones. Then join CJ, search for advertisers that cater to the ringtone market. Apply to those advertiser's programs. Some of them will accept you. Search for banners and other ads for the particular advertiser(s) you like the best and place those ads on your website. If you have good traffic to your site, some of your visitors will click on the ads and a smaller percentage will buy something from that advertiser. Your commission will be credited at CJ and after your balance account reaches $25 or more you will be sent a payment. If you have a site or sites with decent traffic, you can usually find an advertiser at CJ or other affiliate networks that will match your site's content. But you must do the things - SEO, good content, Adwords, etc, that bring traffic to your sites.
maybe you should read a few more forum posts before asking these sorts of questions!! details for cj are all on their website, you should read up on it yourself and that way you may actually remember it.
concur... read about CJ on this forum and others and then follow the advise of others... no one is going to hold your hands on making $$ on the web.