dual displays

is there any way of telling the imac to display the same thing on two screens? im using the mini dvi to video lead and the imac is treating my tv like a second moniter. all i want is to have the same thing on both my moniter and tv at the same time????? please help

Which iMac do you have, and what OS are you using?

i have an imac 2GHz intel core2 duo and running OS X 10.5.2

You need one of these. A mini DVI to Reg. DVI adapter.
http://store.apple.com/us/product/M9321G/B?fnode=home/shop_mac/mac_accessories/displays&mco=Njg1OTEz

And one of these, a reg DVI to HDMI Cable, if its a high def TV.
http://www.newegg.com/Product/Product.aspx?Item=N82E16812226013

My setup is currently a 20" iMac, with a 32" Samsung LCDTV as a secondary display. Works swimmingly. If your TV isn't high def, you'll have to get one of these. An Apple MiniDVI to Composite adapter.
http://store.apple.com/us/product/M9319G/A?fnode=home/shop_mac/mac_accessories/displays&mco=Njg1OTE0