Hi Chris-The-Great,
Unfortunately LimeWire can't control what people share. All we can hope for is that the sh*ts who promote kiddy porn will be prosecuted in the end.

You can go to Tools > Options > Filters > Keywords and tick ignore adult content. You can also filter out certain keywords.

It won't make it go away, will just stop you from seeing as much of it in your searches

If you have the host's IP, you can add them to your blocked list. I think there's an FBI site you can report this to but I can't find it!! Use the search (top right, between faq and home), if you want to find out more.