Hi eduG'rs,
We have built many different camera nest boxes over the years. Some with web cams, some with IP cams along with many other ideas. What we have found is that building the correct box and choosing the best camera is the key.
The nest box has to match the camera. If you have a nest box too short, the viewing distance is all wrong and the box may be too warm for the birds. Don't forget that you will need a bit of light for colour cameras to work.
The choice of camera is very important. There are many cameras that profess to be good bird box cameras. We have found that a dedicated camera has a right lens, correct focal distance, Infra-red intensity for the box.
After many experiments, we did find a perfect camera bird box system from Handykam.com. They offer a plug in and play dedicated kit with everything you need, at a low cost too.
The other bit of advice is to keep experimenting with position of your box. In the right position, the birds will return again and again to raise their broods as well as offering perfect teaching opportunity.
iTeacher.