C., I'm a social worker in an elementary school that was the resident lice checker since it didn't seem to gross me out. So I've checked a lot of heads and picked many a nit out of childrens' hair that didn't have parents that could do what was necessary to get them back in school. Yes, lice are gross, but they are managable. Once you get over the initial shock, you can get into a mode and take care of it. Once you are done, hopefully you will say, "that wasn't that bad". . .hopefully being the key word here :)
Now, I'm not a health nurse, but I'll tell you what I know. Nits are the egg stage of the actual bug. Live nits will be these almost clear flat things stuck to a hair shaft with a type of glue right up next to the scalp. Dead nits will slip down the hair shaft about an inch (they only die with the medicine that you will treat your children with if they are infested), although they are still stuck fast onto the hair shaft. To remove live or dead nits, you must treat the child's head with special medicine that you can get at the drug store, beware, it's expensive. Then you must go through every single part of the head (that takes the longest). When you see one, you must grab it in between your fingernails and pull it off all the way down the hair shaft, or use a comb with small teeth (that never worked for me) - don't worry, it doesn't move or jump at this point. It looks different than dry skin that flakes off, that's not as opaque as the nits. Now I have waist length hair that wasn't tied back as I would be checking kids, and I never got it, nor did I worry, I'm pretty sure the actual lice don't jump as high or far as fleas :)
As far as clothing, brushes, bedding, and couches, etc, there is a specific temperature that you must wash things at (i.e. very hot) but I'm not sure what exactly this process is. You can call your local health dept. and ask to speak to a health nurse, these gals are the ones that are called when school gets an outbreak (my experience is that the Dr.'s office wasn't as helpful as the health dept). They usually have brochures outlining exactly what to do.
Head lice carries a stigmatism that is scary to overcome as a parent. Not to mention that they are rather disgusting. But I've seen all kinds of kids from all kinds of backgrounds aquire the little buggers, they are really quite common, and at a normal school we'd have to check kids at least 3 times a year. Chances are your kids will go through this numerous times during school. It seems that it is one of the things we have to go through as parents, like a rite of passage or something!!
Good luck, and I hope they don't have it. But if they do, you will get through it and hopefully have a few fun stories to tell!