This site would be quite helpful in a variety of subject areas in living environment. There are animations on cells (their replication and organelles) as well as various body systems and DNA technologies. It would add to a lesson in that it would tie up the main ideas in a visual way to help all the students see the material rather than just take notes on it.
Cells alive is a very helpful website that I've already used as a teaching tool. It can be used for mitosis, meiosis and the cell cycle. It shows the cell going through the steps of mitosis and meiosis either animated or a video of the real thing. Moreover, it has detailed explations of each step.
This site is actually a very helpful and nicely made powerpoint. It links the nervous, muscular, and skeletal systems together. It has several animations, notes, pictures, and a quiz at the end. It is a full interactive lesson.
Build a Body is a very nice site that allows the user to, well, buld a body. It is good for the most of the body systems and allows an interactive way to see how the systems work and connect. It should not just be used to make it but should be backed up with information on each piece of each system.
This is a lovely website for almost all topics on genetics, DNA, DNA replication, and protein synthesis. Each topic comes with an animated walkthough of the topic, a video, and a problem to solve. It's a nice addition to a lesson because it not only has a video to help make the abstract topic of DNA more concrete but it also has problems to work on as practice for a test or the regents.