how to fill drop down on the selected index change of another drop down

 in one of my page i have two drop down one is state drop down and another one is city drop down. now when i select the state from the sate drop down then city drop down need to be filled on the basis of selected state. here data are comming from sql server 2005 database.pls send me the related code to do that immediately
 
thanx
deepak

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