How about a few more lighting tips Arlwy? The comparison shots of the frontal flash and the flash off camera was pretty amazing. Helen Henry

I can answer any questions you have but I’m not going to go to any detail here.
I'll just refer you to a strobist site I frequent which should get you all the info you need to know.
This is mostly dealing with off camera flash but its a start.

Look for lighting 101, go through it all, then go to lighting 102. Somewhere in between 101 and 102 you should have an "ah ha" moment. Those are a lot of fun !!! I just wish I got them more often.

http://strobist.blogspot.com/2006/03/lighting-101.html

http://strobist.blogspot.com/2007/06/lighting-102-introduction.html