PPC means Pay Per Click. There are several programs like Adsense, Bidvertiser, YPN, etc. If you have a website or blog, you can apply for these programs. Once approved, just copy paste the ad code. You'll get paid for each valid click.
it's one of the mediums in an internet advertising wherein you as an advertiser will only pay for every click generated. you create campaigns, bid on keywords, customize adtext for your ads and some others.. try using Google Adwords, it works best for me.. just my two cents..
PPC is advertising program. The publisher put the ads on their website, and they get paid once the visitor click on the ads