I am making a Christening Cake and I saw a cake on the internet that had a "stained glass" cut out, probably fondant. What I need to know is where can I get something like that , that looks like a church window? Any help would be greatly appreciated

Sounds like one of the cakes I saw in a Wilton book some years ago. I think there was a pattern for itl, and the decoration was actually run-sugar/color flow. Another option would be to make the cut out of fondant or gumpaste in white- then "paint" in the windows with gel colors or airbrush colors.

If it was me, I'd copy the pic off the internet-enlarge it, and use it as a guide to make my own cathedral window pattern.