Best is MIVA
MIVA is a network of partner sites powering over 2 billion queries per month. When you open an account with MIVA your ad can appear across the MIVA network, which includes sites such as CNet.com, InfoSpace and WorldNews.
MIVA's proprietary bid-for-position technology allows you to set the amount you wish to pay for each keyword.
MIVA provides a full suite of management tools to help improve ROI.
Have you generate sales from MIVA? If you what is the conversion rates as well as what is your CTR and PPC rates? Would you like to share your experience with us?