With PPC search engines, you bid on keywords/phrases and when someone searches for those keywords, your site will appear on the search results page. If someone clicks on your site, you're charged the amount you have bid. If they don't click, your account is not charged.

Overture was the very first PPC S.E. in existence and it's still the largest and most effective. Their success is mostly due to the extensive relationships they have in place with many of the major search engines. When bidding with Overture, the top three bid positions will also appear on some of the majors like Altavista, Yahoo and others. These listings generally show up under the heading of "sponsored links."

Remember, visitors who come to your site via a search engine are already targeted leads, and once they get there it's up to you to convert them into buyers. No PPC S.E. will make the sale for you; that is always determined by the strength of your ad copy. Your site must convert visitors into buyers, and the only way to do that is with strong ad copy that convinces them to take action.

The biggest task in signing up with PPC's is choosing the keywords/phrases you wish to bid on. You don't want to be too broad and bid on one word; you'll do better by being more specific and coming up with or 2 or 3 word combinations to bid on. You don't want to pay for untargeted traffic, and if your keyphrases aren't relevant to your site, that's exactly what you'll be doing.