I am sure everyone knows about this "tip" but may be some one is still not aware of it..so i think this post may be helpful for them as well as for those who know about it but still not able to get a proper and exact color code matching with your blog's content..don't worry my friends here is a link where you will be noticing a hexa color chart which provides more extensive color coding than google,bidvertiser,widgetbucks,amazon and similar ad networks..adjust your color codes according to your main blog/site's content and see an increase in rate of clicks..  i have tried it and got successful in increasing the "clicks" from readers as well as visitors..ofcourse the trick works on "confusing" the traffic..but its "not against rules" and instead its considered "optimization" of your ad codes..
hope you may also be finding it useful..

I used to just leave the google ads at their original set colours but I found that my sites would not bring in any sort of income. After making a few minor changes my adsense earnings have increased drastically.

I find luring people to click on your ads by making them fit in almost crucial, and a definite must if you want to increase your clicks.

It worked for me.
Trying to change the colours of the adds to make it look integrated to the whole site is always a good idea.