The PPC industry is all the rage at the moment. PPC means Pay per click. It's when a surfer clicks on a banner displayed on a publishers website and the publisher is paid per click. The value depends on the agreed price paid by the advertiser to the ad network. The further up stream as a publisher you go, the more money you will make per click.
The best way to find the up stream networks is to see the payouts the are giving out. Obviously the higher the payout the more upstream the network is. You should also check were the company is based and if it is a registered business. Remember you are relying on that network to pay you.
Decide on a network that will pay you well per click. The next thing is see how often they pay their webmasters. And the payment options like PayPal, wire or check. PayPal would be best as you get the money instantly. Also check to see if the network advertisements adult banners as you may not want those on your site.
And once you decide to join an ad network, place their banner near the to of your website so that surfers will see it as soon as they hit your page. Be patient because it could take sometime to start seeing $$$ roll in. Do not put too many banners or ads on your page as that will put off any surfer that may want to return. Also avoid pop up advertising as this also puts the surfer off side.
Good luck in your mission to make money in PPC networks.