[Maurice]

Here is a video that should help.

http://www.woodsmith.com/video/154-RouterTableJoinery.html

The two keys to success are to adjust the bit height so the stock is centered on the bit and the bit should protrode from the fence a distance equal to the thickness of your stock.

Hope that helps,
Brian

Many thanks for that website, it sure solved a lot of problems for me.
Mo