I don't think there is any great option to google adsense till now but yes if you want then can opt for various CPA affiliate networks.

I don;t hink that there is any best alternative for Google Adsense

there is no option best then adsense but if you are net getting adsense then you should go with chitka and CPA

Anyone can detail "CPA affiliate networks"?

Do check out:

Chitika (probvably the top adsense alternative)
Yahoo/Bing Network
Vibrant Media

ofcourse , after google adsense cpa is best getting the money.

try warriorforum.com(A freelance company) affiliate program. it's best CPA.