Sticking my hand up here and confessing that my kids have had lice multiple times. Once one kids gets it it seems to spread like wild fire round the school.
I've done all the chemical treatments over the years and found the only thing that really helps is using a few (quite a few) drops of tea tree oil at the same time as you shampoo, then the age old conditioner aided combing every 3 days. We've just got through a bout and won't expect another for a while as it's so cold now, but when we lived in Singapore the little b*****ds were impossible to get rid of.
I think I'm relatively patient as I had a rather traumatic experience when I was about 10 - I had very long, thick hair and my mother was fed up doing the awful combing routine and me screaming each time, so she grabbed my plait and just cut the whole thing off at the top. Of course, it was all jagged and she then had to take me to the hairdresser to fix it, but told everyone in there that I had nits and I was taken off to a special area for washing, there was much disinfecting of everywhere (in my presence) and everyone in the salon stared at me. I've never forgiven my mother for this one!!
Let me see if I can find a link to this info..... 
