You'll want a good theme such as CTR theme or Clickbump for best results

Here is a list of plugins for AdSense blogs:

Adsense Deluxe
Adsense Injection
AdRotator WordPress Plugin
Adsense Earnings WordPress Plugin
AdSense Manager
AdSense Sharing Revenue and Earnings System
Google Ad Wrap

You can Google them and read reviews of each and then decide which one suits your needs.

I hope that this helps...

To your success,
Tony Alves

Adsense is the best. i like this plugin

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Is there a benefit to using a plugin compared to hard coding the HTML in a widget?

i use simple ads placement
really simple to use