We've just had our first bout of head lice! Dd2 (nearly 4) got them. I found about 12 live lice, which I picked off individually with tweezers (squashed each one!), then treated with Hedrin Once, which claims to kills the eggs too. It said to leave on for at least 15 mins, so we did 20. I had to shampoo quite a few times to get it out the hair.
After that, I could see there were loads more eggs than I had seen at first. They were really easy to see, as they were brown, on light blonde hair. I didn't want to wait to see if they would hatch, so I actually picked them off by hand, using my nail to slide each one off.
The next time I washed her hair, I used the Nitty Gritty comb on wet hair, and this got out quite a few more eggs. I also found 3 eggs on dd1, but no live lice.
This was a week ago, and I've been checking her hair daily since, and touch wood, nothing since.
Check carefully at the nape and behind the ears for eggs, as this was where they all were on dd. Use a torch up close on the partings if there's not a good light.
Probably obvious, but make sure they wear their hair up well for school, so ideally a plait.
Best of luck, they're horrible aren't they!