In the Grade 4 Health curriculum there is a unit on illness and disease. This is the first grade that AIDS is really introduced, and it is one of the diseases that are stressed to talk about. One of the suggestions in the curriculum guide is to have the students write reports on different illnesses or diseases. I found this website on AIDS awarness called the AIDS Handbook.
This site was designed my middle school kids so it is easy to read, and gives a breif but fairly thorough look at the diseases, prevention, trasmition, symptoms, treatment, and how our body fights disease. I think this website is designed for students, it also give some links to other websites about AIDS. I think this can be a very touchy subject so it is good to find some solid online resources for students to look at. I would have this site as one of the options for doing research on this topic. It is not very interactive, but it is fully of useful information and some diagrams to help visualize what is being talked about.