FlightRadar24.com lets you embed their website into your own using an iframe tag. You can modify the parameters to provide your own latitude and longitude, zoom level, and customize the width and height of the embedded frame. Here’s the code used to generate the frame above:

<iframe src="http://www.flightradar24.com/simple_index.php?lat=43.8&lon=-79.4&z=8" width="600" height="600"></iframe>