After trying to take photos of half the family this morning, complete with kids who wouldn't sit still, I thought I'd better check up on my knowledge of Depth of Field settings: if I had got the correct DOF/ aperture, the speed and ISO settings could have been set better.
So, I now know that I should have used the A-DEP setting my Canon, and I have found a nifty bit of software for a Java mobile phone that calculates DOF, courtesy of www.curved-light.net. It is something I have wanted to put together for a while but not got round to learn enough Java to write it. And it gives a good indication of what should (and shouldn't) be in focus.
Finally, a couple of other sites well worth noting are http://www.dofmaster.com/dofjs.html which has an excellent online DOF calculator, and http://www.outsight.com/hyperfocal.html#math which has a calculator and as much information and equations as you will probably ever need.
I guess I should have done all this checking before I took the photos, but still I thought they turned out pretty well...