Oh yeah, someone here told me HAIR SPRAY! And then my DS teacher told me that as well. Personally, I hate hair spray, but I hate lice more! LOL So every day before school, the boys get hair spray on their hair now. Blech, BUT it seems to be working. The lice do not like it, cannot grip on to the hair AND they only like clean hair so the hair w/ hairspray seems dirty to them and they don't like it!
It's a neccesary evil for us right now. LOL
Also, the first 1-2 weeks AFTER we found out they got lice from school, I would spray their hair with tea tree oil and comb their hair out EVERY morning before school. You can also put tea tee drops IN their regular shampoo and that works as well. The school nurse said it only works if you shampoo them every day which we cannot b/c of dry skin, but I do the TT spray every morning so I think that does the trick.
I agree w/ someone else above, all of this stuff makes the scalp very dry.

My boys now have dandruff and dry scalps.
Good luck! I am itching just reading this and do every time I think about it! LOL