Clicksor, AdBrite, Chitika.

To add to the short list above, also check out Addynamo and Intentclick

I checked and tried many and there is no one as good as Adsense..
But if Adsense is not approved for your site,. You can look into combination of other ad network..
Here are some that worked for me:

BuySellads
Vigilink
Chitika

Best Google Adsense Alternatives

Adbrite - low minimum payout but only pays through check
Clicksor - never had much luck with this.
Chitika -good targeting but never had any luck with this too.

CPA offers, especially on a niche site. AdSense makes you lazy.

Just started working at AdsGadget, a self-serve ad platform for publishers and have seen people satisfied with the results. The platform was launched last year and has a lot of solid features; great alternative to Adsense.
Worth checking out,

cheers!

I have worked on different ad networks- must say there is no replacement to Adsense. You can try Chitika, next best to adsense.

Hope this helps.

Adbrite does ok, it depends on if they can pick up the content of your page. I've had reasonable success with PulsePoint as a primary (with a fill rate around 30%), with Adbrite and Addynamo as backup tags for the remaining 70%.

honestly there is no good alternative for Adsense when it comes to PPC . may b you can try promoting Amzon products or any other related affiliate products..