ad placement assistance needed

I want to know how to place a large rectangular ad by wrapping the text around it.

 

you can select that option while you are creating adsense code

 

trichnosis says something totally wrong as far as I know you can't have this while you're creating the adsense code, so if you want to place a large rectangle and the text wrapping around it you have to use a DIV around the adsense code, a DIV with style"float:left"

and after you have your text.

or simply, look at an implementation that you like and look at the source code.